SOME STUDIES ON THE NUTRITIVE VALUE OF THE 
SOYBEAN IN THE HUMAN DIET 



DISSERTATION 

PRESENTED IN PARTIAL FULFILLMENT OF THE REQUIRE- 
MENT® FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN 
THE GRADUATE SCHOOL OF THE OHIO STATE UNIVERSITY 

(Agricultural Chemistry and Soils Department) 



By 
W. G. BOWERS 



The Ohio State University 
1919 



/ 



K 



SOME STUDIES ON THE NUTRITIVE VALUE OF THE 
SOYBEAN IN THE HUMAN DIET 



DISSERTATION 

PRESENTED IN PARTIAL FULFILLMENT OF THE REQUIRE- 
MENTS FOR THE DEOiREE OF DOCTOR OF PHILOSOPHY IN 
THE GRADUATE SCHOOL OF THE OHIO STATE UNIVERSITY 

(Agricultural Chemistry and Soils Department) 



By 



W. G. ROWERS 



The Ohio State University 
1919 






v. •* *>• 

JAN 21 1920 



• • • 

• » 
« • • 



ERRATA: 

Foot note on this page should read ; A thesis presented in 
partial fulfillment of the requirements **** to the Graduate 
School, of etc. 

Note at the bottom of page 324 should read; **** Depart- 
ment of Agricultural Chemistry and Soils, etc. 



SOME STUDIES ON THE NUTRITIVE VALUE OF 
THE SOY BEAN IN THE HUMAN DIET 

By W. G. BOWERS 
INTKODUCTOKY 

Extent of Production 

For a great many years there has been considerable interest in the 
seeds of the legumes in connection with human dietetics. It is commonly 
known that most leguminous plants thrive under more adverse circumstances, 
regarding climatic conditions and soil fertility, than any other plants that 
furnish food products. The work of Wilforth in 1887 established the fact 
that they are nitrogen gatherers, collecting free atmospheric nitrogen which 
becomes stored as protein, and that they are almost indispensable in crop 
rotation. For these reasons, any leguminous plant that would furnish a hu- 
man food should be of interest. 

The common white or navy bean has played a very prominent role in the 
food problems of the United States, especially in supplying nourishment to 
the soldiers in the service and to the laborers on the farm and in the factory. 
The bean has been recommended as the "poor man's beefsteak/' supplying 
as it does, like meat, great quantities of valuable proteins. 

In China, Japan and some other of the eastern countries another legume, 
the soy bean, is used extensively as a human food. This plant (Glycine 
Hispida), now one of the most common of its familiar family, according to 
DeCandolle, occurred originally in the- wild state in Southern Asia from the 
southern part of China to the southern part of Japan and as far as Java. It 
was cultivated and used for food in China before the time of Confucius. 



A thesis presented for the degree of Doctor of Philosophy to the Faculty 
of the Ohio State University. 



279 

This was at least four thousand and seven hundred years ago. It has been 
cultivated and used for human food in Japan also for many centuries. 

In Japan it is now one of the most important of the human foods, being 
second only to rice. That means that it plays the same role with the Japan- 
ese that meat does with the Americans or Europeans. It has been cultivated 
there to such an extent that a great many varieties are to be found, and it 
is used to such an extent in that country that Japan herself cannot supply 
her own requirements. 

Despite the fact that the soy bean has always been so important in 
China, and so very important in Japan from such early times, its introduc- 
tion into suirounding countries has taken place very slowly. But, with very 
few exceptions, wherever it has gone it has established itself permanently, 
and in many places it has increased in extent of production and gained emi- 
nent favor with the people. 

For centuries it has been used in India as a human food, and lately its 
use there has remarkably increased. For several hundred years it has been 
the main crop in Manchuria, where raising the soy bean, making the differ- 
ent commercial products and exporting them, is at present the greatest in- 
dustry (3). In 1910, 30% of the tillable area of Manchuria was devoted 
to the production of the soy bean and one billion kilograms were exported 
to the different countries of Europe. The product equaled about 30,000,000 
bushels. In 1912 this was increased to 90,000,000 bushels. In 1910, $1,000,000 
worth of soy bean products was imported into Germany, which was nearly 
three times as, much as the year before (3). 

When the plant was first carried to Europe, only two hundred years ago, 
it was brought as an interesting botanical specimen. It was studied as such 
for nearly one hundred years before anyone conceived of the idea that it 
was valuable as a food producing plant. 

W. J. Morse (40) tells us that Professor Haberlandt, a little over a 
hundred years ago, began to experiment with the plant in regions of Austro- 
Hungary and published a work in 1878, in which he gave an enthusiastic 
prophesy for the s©y bean and urged its cultivation. He did a good deal of 
work to excite interest in it as a human food, and he also at his own expense 
distributed a great deal of seed among the farmers of his 'country, but after 
his death the interest lagged and finally died away. 

The soy bean has been grown in the United States for many years, es- 
pecially in the Carolinas. Several varieties are now grown to a considerable 
extent in the Northeastern States. But it has been only within the last 
thirty-five years that it has been considered with much favor as a food for 
stock. Only within the last ten or fifteen years has it met with any favor 
at all as a food for man. 

In 1916 over $5,000,000 worth of soy beans were imported into the 
United States (40) and in the same year about 100,000 bushels of American 
grown soy beans were packed as baked beans by several different canning 
companies in the Central and Eastern States (40). In 1917 the amount im- 
ported into the United States more than doubled that of 1916. In 1917 the 



Figures in parenthesis refer to Bibliography 



280 

area in the United States devoted to the cultivation of the soy bean amount- 
ed to 460,000 acres. That is also probably double what it was in 1916. (40) 

Several of the agricultural experiment stations thruout the Eastern 
States (49) have been devoting considerable time and attention to the soy 
bean recently, and, because of the fact that its value as a crop is being 
proven to be greater than many of the crops already grown, the acreage 
given to it has been increasing remarkably. 

Human rood Preparation Made From the Soy Bean 

Manchuria exports to Japan about two-thirds of her entire crop of soy 
beans for the manufacture of food preparations and liquid condiments. The 
chief liquid condiment (Shoyu) is made by mixing cooked ground soy beans, 
salt and water, and inoculating with a rice ferment (Aspergilus oryzae) and 
allowing it to stand in casks for six months or longer. The resulting sauce 
is a liquid of dark brown color whose odor and taste is somewhat similar to 
that of a good meat extract with the exception of being a little more salty 
and a trifle more pungent. This liquid condiment is consumed to a great ex- 
tent by the Chinese as well as by the Japanese. In Japan, especially, the 
manufacture of the condiment is conducted on a large scale, and the yearly 
production (in Japan) is said to amount to nearly 2,000,000 barrels (40). 

A soy milk (Toniu) is made in Japan and China by boiling the finely 
crushed meal in three times the amount of water for thirty minutes, and 
filtering thru a fine cloth filter. The separated liquid is the " Vegetable " 
milk so extensively used in China. Soy milk and soy milk products are be- 
ing made in the United States now. Itano (22) offers the following formula: 
Add to the bean meal five times its bulk of water, inoculate with B-Coli 
and B-Lactis aerogenes as used in salt rising bread, and let stand for sixteen 
hours at room temperature; then boil to foaming for an hour, and filter thru 
cheese cloth. Add to this filtrate salt to the amount of one-half teaspoonful 
per quart. Unless the preparation is being made for diabetes patients he 
recommends the addition of five per cent milk sugar to improve the flavor. 
Condensed and evaporated milks are also made from the above product. 

Soy bean curd (Tofu) is commonly made in Japan by the following 
method: Add to the milk as previously described two per cent mother liquid 
of sea salt; filter off the liquid; press the precipitate in a wooden frame and 
let the pressed curd float in a large quantity of cold fresh water in order to 
free the coagulum from chemicals added. This product is used as fresh Tofu, 
or it may be frozen and put on the market as (Kari Tofu). The frozen prod- 
uct may be kept for years, then used in soups, or fried (Auburaage) and 
eaten like fried eggs or meat. 

The Chinese and Japanese make a soy bean cheese (Miso) by precipita- 
ting protein from the above described milk by the addition of magnesium or 
calcium salts. The grayish white curd is separated out, drained and pressed, 
and then allowed to ferment. This product serves as the basis of numerous 
fermented, smoked and dried cheeses used by the Oriental people (40). 
Some American preparations are made as follows (22) : 
Boiled beans are prepared by soaking the beans twenty-four hours in 



281 

water (changing the water three or four times), applying hot water a couple 
of hours before cooking, adding one teaspoonful of soda per quart of beans 
and boiling in a double boiler for four or five hours. 

Baked beans are prepared by treating as above and baking like other 
beans. 

Roasted beans. Soy beans may be roasted in an oven or ordinary corn 
popper. They are heated until the beans are burst like popcorn. The beans 
thus roasted may be softened by immersing in a syrup while they are hot. 
This is said to make a wholesome candy. The roasted beans may be powdered 
and used as a salad dressing or employed as a substitute for coffee. 

Raw soy bean meal is sometimes mixed with flour to make bread, biscuits 
or muffins. One part of bean meal mixed with four parts of wheat flour 
makes a palatable bread which is very nutritious. Bread made of soy bean 
meal alone is recommended for diabetes patients, since it contains only small 
amounts of starch and sugar. 

Varieties and Chemical Composition 

There are many different varieties of the soy bean. The varieties are 
based on color, size, shape and especially on the time required for the seed 
to mature. The early varieties are generally chosen to grow for seed and 
seed products. 

The flavor and palatability of the different varieties of the soy bean do 
not appear to have been sufficiently tested. Of all the varieties grown in the 
cotton belt, the one said to be the most suitable for human food is the 
"Mammoth Yellow." It has a beautiful color which appeals to the eye. 
It is an excellent oil yielder and the mill operators like it because the oil 
is easily expressed. It yields a good looking meal, and the farmers and 
feeders like it because it does not show any darkness which makes them 
suspicious that the meal is damaged or spoiled. It is the meal from this 
variety which is most used as a human food in this country. 

In the Ohio Experiment Station (49), about 70 varieties have been 
tested each year for the past six years. We have below tabulated a few of 
the yellow, early and prolific bearers. 



Variety 


Beans 


to 10 


grs. 


Blossom 


Ripen 


Yield 


in bu. per acre 


Elton 




55 




7—25 


9—24 




26.51 


Manchuria 




68 




7—24 


9—16 




24.21 


Ohio 7496 




43 




7—24 


9—25 




28.00 


Ohio 9016 




53 




7—25 


9—25 




29.22 



We would judge from the above table that the Ohio 7496 and Ohio 9016 
are the best varieties for the Middle Eastern States, and that the Elton and 
Manchuria, on account of their maturing ten days earlier, would be well 
fitted for the States farther North. 

The ''Early White" variety is said to be the most excellent variety to 
grow in the New England States, especially when a crop of seed is desired. 
The chemical analysis of a few representative varieties are here tabu- 



282 

latecL In the eight analyses can be found the extremes in content of every- 
thing but water. They are all calculated on a uniform moisture content of 
10 per cent. 

Variety Water Ash Protein,Nx625 Fiber N-free extract Fat 

Itosan 10.00 4.90 39.29 3.91 26.64 15.26 



Quebec 


10.00 


5.64 


40.46 


3.68 


24.88 


15.34 


Kentucky 


10.00 


5.54 


36.55 


4.37 


26.82 


16.72 


Medium Yellow 


10.00 


4.68 


40.99 


3.79 


25.27 


15.27 


Manhattan 


10.00 


7.77 


40.66 


3.67 


23.58 


14.32 


Arlington 


10.00 


5.19 


35.07 


5.81 


29.55 


14.38 


Mikado 


10.00 


5.33 


33.15 


5.03 


29.59 


16.90 


Hollybrook 


10.00 
10.00 


5.73 
5.59 


38.49 


4.28 
4.32 


28.44 


13.06 


Average 


38.08 


26.85 


15.16 



4.90 


4.40 


45.70 


1.90 


22.60 


20.50 


4.20 


4.20 


43.10 


2.20 


24.90 


21.40 


3.00 


5.00 


42.30 


5.40 


24.50 


19.80 


4.40 


4.60 


42.30 


4.70 


25.80 


18.20 


7.80 


4.40 


39.80 


3.90 


24.90 


19.10 


6.50 


4.10 


41.00 


3.40 


25.00 


20.00 


4.60 


5.10 


42.90 


4.20 


22.40 


20.80 



Selected from Street and Bailey (59). 

The following table shows the analyses of some typical commercial soy 
bean flours. 

Water Ash Protein,Nx625 Fiber N-free extract Fat 

Commercial soy 
bean flour of some 
different varieties. 
These are flours 
from oil extracted 
cakes. 

Average 5.10 4.50 42.50 3.70 24.50 19.90 

From Street and Bailey (59). 

By comparing the above tables we see that the flour contains muct 
more protein and fat and less of all other ingredients. This is probably 
due to bolting and other purifying processes. 

Character of the Carbohydrates of the Soy Bean and Its Bearing on Nutrition 

The soy bean has a variety of carbohydrates, altogether amounting to 
from 22% to 29% (39) (59). depending on the variety and maturity of the 
bean. The mature seed has no starch. The fresh green beans, those that 
have been dried without being allowed to ripen thoroly, or those that have 
ripened on the vine after the vine has been pulled show slight amounts of 
starch (53). In spite of the almost complete absence of starch analyses of 
the commercial flours made from the soy bean and put on the market for 
diabetes patients show from 20 to 25 per cent of nitrogen-free extract. 
Several authorities have found galactan in the soy bean; Lavallois (30) 
found as high as 11 per cent. Pentesans vary from a trace in the coarser 
varieties to over 4 per cent in the finer varieties. Borhehesani (7) found 
3.86 per cent in one of the finer varieties, and Street and Bailey (59) found 
4.94 per cent in the Hollybrook variety. 



283 

Some varieties of the soy bean have been found to contain small 
amounts of rafhnose. Street and Bailey (59) found 1.13 per cent in the 
Ho.Iybrook variety. The writers found 0.37 of one per cent in a sample of 
commercial soy cake meal from an unknown variety of bean. Euhrah (53) 
found from nine to ten per cent of cane sugar in several different varieties 
Potts (51) says he has found twelve per cent. This is not an inconsiderable 
amount of this kind of sugar for any kind of vegetable. It compares very 
favorably to the amount of cane sugar in the sugar beet when it was first 
cultivated for its sugar content. Street and Bailey (59 round only 3.31 
per cent in the Hollybrook variety. They also found 5.73 per cent of re- 
ducing matter after hydrolysis of the malt extract. Of this. 2.59 per cent 
was found to be galactan and pentosan combinations. The remaining 3.14 
per cent was considered as dextrin, vegetable gums and mucilages. 

Character of the Fats of the Soy Bean and Its Bearing on Nutrition 

The proportion of fats in the soy bean is high, ranging from fifteen to 
twenty per cent (23). Some Japanese experimenters have found the fats 
of food preparations of the soy bean to have a digestibility factor of from 
ninety -five to ninety-seven per cent. Their preparations are not made in such 
a way that the digestibility factor of fats would be increased. 

According to AEathes and Dahles (32) soy bean oil contains ninety-four 
per cent fatty acid, eighty per cent of which is oleic, linoleic and linolenic. 
Then there are small quantities of free fatty acids. We would expect such an 
oil as this with its great amount of unsaturated fats to be very digestible. A 
later report by the same authors (33) gives 0.7 per cent of the soy bean oil 
aa unsaponifiabie. Of this unsap'onifiable fat. one-half is solid and the other 
half liquid. The solid is made up of two different types of phytosterol, a 
substance which can easily be changed in the human body to cholesterol (26) 
which is of very great physiological significance to the body, even tho it 
does occur in small quantities. 

KeimatEu 24] says that soy bean oil contains about twelve per cent of 
saturated fatty acids, mostly palmitic, and some stearic; eighty per cent of 
M^saturated fatty acids, fifty per cent of which consists of linoleic isomers. 
He says the oil contains two-tenths of one per cent phytosterol. 

Euatta and Testoni (54), who expressed the belief that the soy bean 
would become a very popular food, commented especially favorably on the 
amount and character of the fats as valuable in human diet. They analyzed 
nine varieties finding an average of IS. 36 per cent of fat and. in addition to 
this, 1.62 per cent of lecithin. 

Character of the PTOtein and Its Bearing on Nutrition 

The protein eontent of the soy bean is remarkable, ranging from thirty- 
four to forty-five per cent in different varieties in the bean itself (43) and. 
of course, more in the commercial flour and soy cake meal. Not only thi 
amount of the protein? in the soy bean produces, but their excellent char- 
acter, and the varieties and amounts of amino acids which they yield on di- 
gestion, make them of value as a food. The protein is mostly glycinine and 
yields on digestion the following amino acids (43): 



284 

Per cent 

Glycine 0.97 Glutamic Acid 19.46 

Valine 0.68 Tyrosine 1.86 

Leucine 8.45 Arginine 5.12 

Proline 3.78 Histidine 1.39 

Phenylalanine 3.83 Lysine 2.71 

Aspartic Acid 3.86 Ammonia 2.56 

Tryptophane Present 

The protein of the soy bean is very similar to that of cow's milk, which 
yields a similar list of amino acids in the following percentages (1): 

Per cent 

Glycine 0.00 Glutamic Acid 15.55 

Valine 7.20 Tyrosine 4.50 

Leucine 9.40 Arginine 4.84 

Proline 6.7 Histidine 2.59 

Phenylalanine 3.20 Ammonia 1.61 

Aspartic Acid 1.40 Serine 0.50 

Tryptophane 1.50 Lysine 5.95 

The milk made from the soy bean seems to be not only a nourishing 
food, but it serves as a check on the very prevalent summer diarrhoea com- 
mon to children. 

Sinclair (58) experimented on babies, who had various ailments, and 
found that the soy milk brought improvement in the great majority of cases, 
curing diarrhoea and intestinal disturbances. He found that it was easily 
digested and easily excreted. 

Also a cheese, hard to distinguish from cow's milk cheese, has been 
made from the soy bean protein. In some cases cow's milk cheese has been 
adulterated to the extent of fifty per cent with soy bean cheese, and has 
been sold on the market for months before the adulteration was detected 
(31). 

Seme Japanese experimenters found in the soy bean as much as 6.9 per 
cent of albuminoid nitrogen. This figured in terms of protein would amount 
to about forty-two per cent. 

The protein of the soy bean yields on digestion a complete amino acid 
mixture. According to Osborn and Mendel (44) rats will grow very nearly 
normally on glycinin. They also proved that cystine, lysine and tryptophane 
had to be added to any protein that does not contain them, in order to make 
it growth promoting. These the soy bean has. Osborn and Mendel (45) 
proved that the proteins of the soy bean, unlike those of other leguminous 
seeds thus far investigated, are adequate for promoting growth. The same 
authors (46) also demonstrated that if the protein of corn, which lacks the 
above amino acids, was supplemented with the protein of the soy bean, 
growth was satisfactory. 

Vitamines of the Soy Bean 

Daniels and Nichols (15) in their investigation of the nutritive value of 
the soy bean studied in a qualitative way the vitamine content. Experi- 



285 

menting with rats, they found that a diet containing sixty per cent of soy 
beans, the only source of the vitamines, made possible the production and 
rearing thru the suckling periods two successive litters of young. They 
found also that rats grew normally on a diet containing fifty per cent soy 
beans and that the females produced young at an early age. 

Osborn and Mendel (44) experimented with rats with a view of deter- 
mining the vitamine value of the soy bean. They used a diet of either soy 
cake meal or cooked soy bean meal, together with an added salt mixture of 
the proper kinds and amounts of different salts, pure starch, butterfat and 
lard. They reported that the rats completed their normal growth in the 
normal length of time. This shows that the soy bean has a sufficient amount 
of water soluble vitamine for the promotion of proper growth. 

When lard entirely replaced the butter fat, the rats grew normally for 
over two hundred days without showing any symptoms of nutritive decline. 
This is much longer than the majority of rats, undergoing experiments for 
vitamine determination, have grown on a diet without the addition of fat 
soluble vitamine from some special source like butter-fat. It seems, there- 
fore, that there is in the soy bean sufficient of the fat soluble vitamine to 
promote proper growth. The experimenters did not notice any eye soreness 
common to rats on a diet lacking sufficient of the fat soluble vitamines. The 
rats that had the soy meal, which did not have the fat extracted, grew a 
great deal better than those that had the extracted meal. So far as is known 
at the present time the soy bean is the only seed, with the possible ex- 
ception of flax and millet, which contains sufficient amounts of both the 
water soluble and the fat soluble vitamines for the promotion of proper 
growth. 

Minerals of the Soy Bean 

Circumstances naturally place upon man or animal a limit to his free 
choice of foods. The habits of man's ancestors narrow him down to certain 
diets regardless of their chemical composition and the nutritive requirements 
of his organism. On this account he has to consume a surplus of some things 
in order to get sufficient of others. It has been proven that an animal will 
grow and fatten on less of certain food if he has free access to certain 
mineral salts. This being denied he will consume greater proportions of the 
food in order to get the salts in required amounts (17). The consideration 
of the mineral content of a food is assuming more importance now than ever 
before. 

Osborn and Mendel (44) carried on a series of experiments with the 
view of determining the mineral content of the soy bean as related to the 
growth of young rats. They found that like the other seeds it is lacking in 
these, especially in calcium. 

Dr. E. B. Forbes of the Ohio Experiment Station has given us consider- 
able data on the mineral content of different food materials. From one of 
his tables we have taken the following data on the soy bean, along with 
three legumes generally used as foods: 



286 

K Na. Ca. Mg. S. 01. P. 

Soy bean 2.095 .380 .230 .244 .444 .025 .049 

Navy bean 1.390 .086 .235 .206 .224 .047 .429 

Cow pea 1.636 .189 .117 .243 .280 .047 .532 

Pea 061 .563 .068 .180 .254 .024 .399 

The calcium and phosphorous are the chief elements sought for in this 
connection. We shall notice in the table that the soy bean is second in cal- 
cium, having only 0.005% less than the navy bean, and that in phosphorus 
the soj bean is by far richer than the others. 

The Soy Bean Compared to Some Other Legumes Used As Human Food As 
to Fuel Value and Organic Nutrients 

Fuel Protein Fat Carbohy- 

Food Value (NX 6.25) percent drates 

per lb. per cent per cent 

Navy beans 15.65 22.5 1.8 59.6 

Lima beans 15.86 18.1 1.5 65.9 (5) 

Cow peas 15.50 21.4 1.4 60.8 

Peas 16.11 24.6 1.0 62.0 

Soy beans ....17.77 38.0 15.0 26.8 (59) 

In this table we notice that the soy bean is superior to the other le- 
gumes in fuel value, that while its carbohydrate content is less its protein 
and fat contents are much greater. 

Digestibility of Soy Bean Products 

Obviously chemical analyses alone do not measure the nutritive value of 
a food. We must know also the digestibility of the food, the relative quality 
of its proteins, carbohydrates, fats and minerals, the extent to which acces- 
sory substances or vitamines occur, and whether for any reason it exerts a 
harmful influence on the body. 

Some observations by Oshima on some of the Japanese food preparations 
indicate that the digestibility factor is high, protein 89.2 to 96 per cent, fat 
95 to 97 per cent, carbohydrates, including fiber 88 to 98 per cent. The Japa- 
nese method of preparation (involving fermentation) might have some in- 
fluence on the digestibility factor. 

Mendel and Fine (35) found the proteins in mush prepared from soy 
beans to be from 74.5 to 87.6 per cent digestible by dogs and 85.3 per cent 
digestible by men (uncorrected for the metabolic factor). In fact, the pro- 
teins of the soy been were only 2.6 per cent less digestible than those in a 
mixed diet of wheat, meat, eggs and peanut butter. The protein of the com- 
mon white bean baked in the usual way was distinctly less digestible, viz., 
77.9 per cent, in the human subject. The experiments of Waite on the di- 
gestibility of wheat, and of beans agree with this result. Daniels and Nicolls 
(15), from experiments on rats, have concluded that the proteins of the soy 
bean are highly efficient in promoting the growth of young animals; in fact, 



287 

about as efficient as those of milk. On the other hand, the proteins of the 
white bean appear to be decidedly poorer in quality or about as valuable as 
those of corn (34). 

The nutritive quality 'of the white bean is further lowered by the pres- 
ence of considerable amounts of carbohydrates, e.g. hemicelluloses, which are 
indigestible by man, and which ferment in the intestine with the production 
of large quantities of gas, resulting in discomfort and even in injury to the 
intestine because of the stretching effect of the gas (34). The carbohydrates 
of the soy bean appear to be more digestible and less prone to intestinal 
fermentation. 

Mendel and Fine (35) in comparable experiments with dogs, fed in one 
ease soy bean flour and in the other a preparation made from hulled white 
beans. They found five times as much crude fiber, and more than three 
times as much hemicellulose in the feces of the white bean fed animals, as 
in the feces of the soy bean fed animal. In the human subject the weight of 
the air dry feces from the soy bean feeding was increased only four per cent 
above the mixed diet period, while on the white bean diet the increase in 
weight of air dry feces was 68 per cent, indicating a good utilization of the 
nonnitrogenous material in the first case and a poor utilization in the second. 

In the light of the above information it would appear that the nitrogen 
free extracts, as a whole, in the soy bean, as well as the protein in certain 
of the soy bean products, are much more highly digestible than are those of 
the navy bean. 

EXPEEIMENTAL PAET 

In our experimental work w r e propose to inquire into the digestibility of 
soy cake meal. We shall then determine the digestibility of the different 
carbohydrates as found in a representative variety of the soy bean. After 
passing some of the beans thru a milling process we shall study the compo- 
sition and digestibility of the meal and bran and determine their relative 
amounts of calcium and phosphorus, and locate any possible poisons or ob- 
jectionable substances that may be present in either of these. This will 
make it possible, then, to determine whether or not it would be profitable 
to carry on the milling process and eliminate certain products, or whether 
by the use of certain extractives we can get rid of the objectionable con- 
stituents. 

The Character of the Material Used, in the, Experiments 

In the following experiments on digestibility the samples of soy cake 
meal were obtained at different times from southern oil mills. What varieties 
or what proportions of the different possible varieties represented were not 
known to us. The meals were both rather coarse and somewhat gritty. Be- 
fore using we ground them fine enough to pass thru a twenty mesh sieve. 

For the experiments on the milled products we used a sample of the 
whole beans, furnished us by the kindness of the Farm Crops Department of 
the Ohio State University. 



288 

DIGESTIBILITY OF SOY CAKE MEAL BAKED INTO BEEAD 

Experiment I 

The subject was a healthy man, aged 38, weight 160 pounds, engaged in 
moderately active laboratory work each day. Since, obviously, it is im- 
possible to consume with relish an exclusive diet of soy bean meal, a mixed 
diet was selected containing a few articles of known digestibility in ad- 
dition to the soy bean meal, the chief constituent. The feces from the three 
day experimental period were marked off with lampblack taken with the ap- 
propriate meals. Soon after collection of the stools, they were moistened 
with alcohol containing a little sulphuric acid, dried on the steam bath, 
brought to an air dry condition by exposure to the atmosphere of the labor- 
atory and thoroly pulverized. The protein was determined by the Kjeldahl 
method (NX 6.25); fat by the Gephart and Csonka method (19), nitrogen 
free extracts, fiber and ash by the ordinary routine methods. 

The soy bean meal used in this experiment had the following com- 
position : 

Per cent 

Moisture 6.5 

Ash 5.7 

Protein 44.1 

Crude fiber 5.9 

Fat 3.3 

N-free extract 35.5 

Two hundred grams of this meal was mixed with four hundred grams of 
patent wheat flour and ten grams of sugar and made into yeast raised bread. 
This bread was of good texture and highly palatable. 

The diet for the three days was as follows, approximately one-third be- 
ing consumed each day. 

Protein Fat N-Free 

Grams grams grams Ext. grams Calories 

Soy bean meal 200 88.2 6.6 71. 696 

Pat. wheat flour 400 53.2 6.0 288. 1420 

Milk 3000 103.1 120.0 141. 2064 

Butter 200 170.0 1530 

Cane Sugar 200 200. 800 

Total 4000 244.5 302.6 700. 6510 

Per day 1330 81.5 100.8 233. 2170 

The feces from the three days weighed 248 grams moist, and 66.6 grams 
air dry. They contained: 

Per cent Grams 

Moisture 7.25 4.82 

Ash 19.70 13.12 

Protein 27.66 18.82 

Crude Fiber 8.46 5.63 

Fat 22.01 14.65 

Nitrogen-free Ext 15.22 10.14 



289 

In addition to undigested food residues, feces always contain metabolic 
products derived, first, from the digestive fluids; and second, from mucous 
and epithelial cells from the walls of the digestive tract. In order to de- 
termine the amount of these metabolic products, a basal ration consisting of 
milk, butTir. sugar, -:;\rch and agar, designed to yield feces of about the 
same bulk as in the soy bean period, was taken. 

The diet was as follows 

.: : : : r- :- s ~ : .:± 

275 grams butter 
350 grams eane sugar 

130 grams potato starch, boiled in water to make a pudding 
grams agar, eaten dry and raw* 

One-third of the abovf was :nsumed daily for a three-day period. 

The resulting feces weighed 270 grams moist and 55.6 grams air dry and 

contained: 





Per cent 


Grams 


Moisture 


5 : 


2.95 


ArYi 


1950 


: :<.5 r 


- — pin 


n.po 


■?.•?: 


"-■- 


si ?n 


::.s- 


1 ? i n 1 e Iber 


L4t 


.77 


X-free : _ : : :•: 


...30.60 


17.03 



The protein in the feces of this period represents metabolic products 
from the- digestive juices and intestinal walls as well as some unabsorbed 
protein from the milk. Deducting this from the protein eliminated in the 
feces during the soy bean period we have 18.82 — 6.60 = 12.22 grams, which 
represents the unabsorbed protein from the wheat flour and soy bean meal 
This gives a coefficient of the total protein of the bread of 91.5. Asr.L-inr 
that protein of patent wheat flour is 88.6 (64) per cent digestible, the co- 
efficient of digestibility of the soy bean meal protein becomes 93. This is 
hardly fair, however, since the coefficient 55 .€ was obtained without making 
a correction for metabolic products in the feces. We feel safe in concluding. 
however, that soy bean meal, prepared as in this experiment, is as digestible 
as regards its protein as is the protein of fine wheat flour which stands su- 
preme among the cereal grains in this respect. 

The carbohydrates of bread made from fine wheat flour are 97.7 per cent 
absorbed in man (17), milk sugar 99 (5) per cent and cane sugar probably 
100 per eent. Using these values, the Xitrogen-free extract of the soy bean 
meal is found to have a coefficient of digestibility of 96.9 per cent. 

DIGESTIBILITY OF SOY CAKE }1EAL AJXSH 
Experiment n 
In this experiment the soy bean meal was prepared as a porridge 'by 



'Agar had 6.35 per cent ash and 15.75 per cent of moisture. 



290 

cooking five hours in a double boiler. This sample of meal contained more 
grit than that used in Experiment I, but not enough to increase the ash 
content greatly. It had the following composition: 

Per cent 

Moisture — - 4.17 

Ash 5.80 

Protein - 49.31 

Crude fiber 5.10 

Fat 6.50 

Nitrogen-free extract 29.12 

The diet for the three day period contained the following, approximately 
one-third being eaten each day: 



Grams 

Milk 2000 

Butter 150 

Cane sugar 300 

Soy bean meal .*. 370 



Protein 


Fat 




N-Free 




grams 


grams 


E 


xt. grams 


Calories 


70. 


80. 
127.5 




94. . 
300. 


1376 
1147 
1200 


182. 


24. 




108. 
502. 


1375 


252. 


231.5 


5098 


84. 


77.2 




167. 


1699 



Total 2750 

Per day 917 

The fecal residue from the above food weighed 224 grams moist and 58.1 
grams air dry, and contained the following: 

Per cent Grams 

Moisture 4.40 2.56 

Ash 20.64 11.19 

Protein 39.90 23.20 

Crude fiber 7.00 4.06 

Fat 18.96 11.00 

N-free extract 9.00 5.22 

Assuming that 6.06 grams of protein represents the unabsorbed protein 
of the milk plus the metabolic protein from the digestive fluids, etc., an 
assumption that cannot be far from the truth, then the unabsorbed protein 
from the soy bean meal must be 23.20 — 6.60 = 16.60 grams. This gives a 
coefficient of digestibility for the protein of the soy bean meal of 90.90. If 
the carbohydrates of milk are 99, and cane sugar 100 per cent absorbed, 
then the coefficient of digestibility for the nitrogen-free extract of the soy 
bean meal is 96. 

In this experiment, as in Experiment I, we cannot calculate accurately 
the digestibility of the fat, but we are not particularly concerned with that 
phase of the subject at this time. By adopting proper experimental pro- 
cedure, one might determine satisfactorily the digestibility of soy bean fat, 
but for that purpose the amount of the experimental fat should be largely 
increased while other fats in the diet should be reduced to a minimum. 



291 

It appears from these experiments that the digestibility of soy bean 
meal, prepared as a bread by mixing with wheat flour, or as a porridge, is 
highly digestible by man, the factors from the two experiments being 91.3 
and 90.9 for the proteins, and 96.9 and 96 for the carbohydrates. 

A STUDY OF THE NUTRITIVE VALUE OF THE NITROGEN 
FREE CONTENTS OF THE SOY BEAN 

As described on page 289, we found the digestibility of the carbohydrates 
of the soy bean as a whole to be 96 per cent. According to the estimates 
of Oshima (47) (51) and others, the digestibility of the carbohydrates of 
different varieties of the soy bean seems to vary widely. It would be only 
reasonable to suppose that the wide difference in these determinations was 
due to the fact that different varieties were used in the various cases. Then, 
too, these differences might be accounted for by two factors; first, the same 
carbohydrates might have different digestibility factors in the different 
varieties of the bean; second, the different combinations of the various carbo- 
hydrates in the different varieties most undoubtedly would have different 
digestibility factors. (60) (25) (14) (29) (55). 

But the first factor, in the opinion of the writer, would be of very little 
significance, while the second would be the one most likely to be responsible 
for the difference. 

By references given above (53) (51) (59), we see that one variety may 
have as much as twelve per cent of sucrose, while others have only three. 
The amounts of starch, dextrin, pentosans, galactans, waxes, fiber, etc. might 
also vary in like proportions. Consequently, a variety with much sucrose or 
dextrin and little of the waxes or fiber would be likely to have a high di- 
gestibility factor for its nitrogen free extracts, w T hile one with high wax or 
fiber content and low sucrose or dextrin would have a low one. 

It is our purpose in this investigation to determine the digestibility 
factor for each different carbohydrate in a certain sample of the soy bean. 
We shall consider it fair to assume that these factors hold good for all 
varieties. So, when we have determined the different carbohydrates of a 
sample, we can estimate the digestibility of the carbohydrates as a whole. 

There are some carbohydrates peculiar to the soy bean and to some other 
materials used for food, like cane molasses, cotton seed meal and a very 
few others. On the assumption that it is of interest from a biochemical 
standpoint to know how digestible is the raffinose and other rather peculiar 
carbohydrates of the soy bean, we are giving this data. 

Kuriyama and Mendel (27) have determined that raffinose is digestible 
in dogs and rats, but that the greater part of the digestion takes place in 
the large intestine. Later Kuriyama (28) found that the sterile extract of 
feces of man, pig, dog, rabbit and guinea pig, having raffinose in their diet, 
usually contain small amounts of raffinose. 

In the following experiments, we made duplicate determinations on one 
variety of the material *meal No. II in the foregoing experiments. In the 
following described work, we determined the different carbohydrates in the 
sample according to the methods used by Street and Bailey (59), with few 
departures, and our description emphasizes only the departures. 



292 

Determination of the Parts in the Meal 

After removing the fat with petroleum ether (boiling point 75 °C) from 
20 grams of the material, the fat free meal was boiled for eight hours with 
95 per cent alcohol under a reflux condenser. After filtering, the residue was 
dried and weighed (weighing 16.06 grams), and preserved for further deter- 
minations. Twenty grams more of the same sample, after having the fat ex- 
tracted in the same way, were extracted for sixteen hours in a percolating 
extractor with 95 per cent alcohol and, in this sample was left 15.6 grams 
of the residue when dried. The entire filtrate in each case was evaporated 
almost to dryness, made up to 200 cc. with water and the mixed materials 
separated into two divisions by precipitating the organic acids, waxes, etc., 
by means of basic lead acetate. 

Two drops at a time of a saturated solution of the acetate were applied 
until a small amount of the filtered solution gave no further precipitation. 
About two cubic centimeters of the lead acetate were required. The excess 
of lead was removed by adding one cubic centimeter saturated solution of. 
anhydrous podium sulphate. Then, by filtering, we obtained the rather 
straw-colored solution containing the water soluble and the alcohol soluble 
carbohydrates. 

The Determination of the Carbohydrates Not Precipitated by the 

Lead Acetate 

In this solution made up to 200 cc. we made reduction tests and took 
polarization readings as follows: 

The copper reduction test as applied before inversion yielded an almost 
negligible result. An aliquot of 50 cc, corresponding to 5 grams of the 
original material, yielded on'y 0.0072 grams CuoO, equal to 0.06 per cent 
of invert sugar. After inverting 100 cc. of the solution, by treating with 
5 cc. concentrated hydrochloric acid and allowing to stand over night, 
aliquots representing 5 grams of the original material yielded 0.3750 grams 
CU2O, equal to 3.68 per cent of sugar calculated as invert sugar and sucrose. 

Before inversion, polarization readings were taken and calculated to 
normal condition. We used the equivalent of 20 grams of the original 
material in 200 cc. of the filtrate, which was taken as the basis upon which 
to make the calculations. This gave us a concentration of 20:200 or 
10:100. The normal concentration was taken as 26.048. Therefore, the 
readings we obtained were taken as 10/26.048 of the normal. Our results 
averaged 1.49° "Ventzke. 1.49 == 10/26.048 of 3.9. Hence, our normal direct 
reading was 3.9° V. After inversion with hydrochloric acid over night, 
calculating in the same manner, we obtained an average reading of — 1.1 V. 
Our readings were taken in a 20 mm. tube at 22° C. 

A sucrose solution having- a direct polarization reading of 3.9° should 
have after inversion a reading of — 1.6 V. Our invert reading, — 1.1, in- 
dicates that there is present a simple sugar, or a complex one which hydro- 
lizes into dextrorotary sugars, which offset the levular rotation. This sugar, 
if a complex one, can be neither dextrose nor maltose. These sugars would 
have had more reducing power in the original unhydrolized mixture. This 
could be none of the simple sugars. Levulose would cause a still greater 



293 

levular rotation. Dextrose or galactose would have exercised a greater 
reducing power than was found in the original solution. 

We applied the Emulsin Test for the presence of raffinose (41). We 
added 0.5 gram of emulsin to 50 cc. of the direct solution and 50 cc. of 
water, and the mixture was kept at a temperature of about 40 °C for two 
hours. This gave a decided increase in reducing power over a similar 
nreparation which had been boiled to prevent the action of the enzyme. 
We concluded as did Street and Bailey (59) that this sugar must be 
raffinose and applied Creydt's formula for estimating sucrose and raffinose. 

In the formula: 

a = direct polarization 
b = invert polarization 
0.5188 (a— b) 

Sucrose = = 3.03 per cent 

0.8452 
a — sucrose 

Eaffinose = ■ = 0.47 per cent 

1.852 

These two sugars after inversion amount to 3.5 per cent. By reduction 
they amount to 3.68 per cent. 

The Determination of the Materials in the Lead Precipitate 

After subtracting the 6 per cent or 1.2 grams of fat extracted by means 
of benzine, and the 3.65 per cent, or 0.7 grams of sucrose and raffinose, 
extracted with 95 per cent alcohol, we had a remainder of 18.1 grams. Of 
the original 20 grams so extracted we had a residue of 16.06 grams. This 
leaves 2.04 grams or 10.2 per cent of the original material to be expected 
in the lead salts. 

The lead precipitate was decomposed with hydrogen sulfide. The 
hydrogen sulfide gas was passed thru a paste, made of the precipitate by 
using just enough water to wash the precipitate from the filter. The pre- 
cipitate was washed thoroly with water and, the washings were added to 
the filtrate. The clear filtrate was then warmed sufficiently to remove the 
excess of hydrogen sulfide. After the hydrogen sulfide had been removed 
the remainder was made up to 200 cc and the organic acid content de- 
termined, according to Schulze (57). Aliquot parts of 50 cc. were evapor- 
ated to about half their volume; treated with 2 or 3 cc. of a saturated 
solution of strontium hydroxide and 150 cc. 95 per cent alcohol; heated on a 
steam bath and filtered while hot. The precipitate was ignited to the 
oxide and titrated with a standard citric acid. It required 0.08 grams of 
citric acid to neutralize the equivalent of five grams of the original sub- 
stance. This gave a percentage of 1.6 citric acid. We reckoned all the 
organic acid content as citric acid. 

In one aliquot of the above liquid the pentozans were determined 
(official method 42) and found to be 0.9 per cent. The remaining 7.5 per 
cent of the alcohol extract was reckoned by difference as waxes, color sub- 
stances, etc. 



294 

Materials in Cold Water Extract 

The alcohol extracted residue for each of the two portions amounted 
to 16.06 and 15.60 grams respectively. This was digested with 200 cc. 
cold water for thirty-six hours. During this time the digests were pro- 
tected from bacterial decomposition by means of a film of toluene. At the 
end of the time the water extracts were partially evaporated at a temper- 
ature of 60° — 70° C. We kept the temperature below 70° in order to pre- 
vent a possible hydrolysis which might occur on account of the slight acid- 
ity of the material, and above 50° to dissolve soluble starch. After the 
partial evaporation, a little sodium carbonate was added to neutralize the 
faint acid reaction. The solution being opalescent, we treated as usual with 
lead acetate, and then made the solution up to 200 cc. 

The direct polarizations calculated on a basis of normal conditions were 
12.90° Ventzke in the first portion, and 12.86° in the second. The invert 
polarization? were 6.50° and 6.40° respectively. 

The copper reduction tests on the water extracts before inversion were 
entirely negative in both cases. After inversion aliquots, representing 1 
gram of the original substances, yielded 0.1655 and 0.1660 grams CuoO for 
the two samples respectively. The average of these two (0.1658) according 
to the "Munson and Walker's Table" is equivalent to 0.0736 grams of 
dextrose. The molecular weight of dextrose is 180 and the molecular weight 
of dextrin is less by one molecule of water or 18. Therefore, we reduced 
the 0.0736 one-tenth of itself which left 0.0663 grams to be considered as 
dextrin. This is 6.63 per cent of the original substance. We estimated 
this fraction of the carbohydrates as dextrin beeause its behavior with the 
95 per cent alcohol, the Fehling's Solution and the polarimeter, shows 
that it is for the most part dextrin and vegetable gums, with some possible 
soluble starch and hemicelluloses. 

The Disaccharides or Trisaccharides would have been extracted with the 
95 per cent alcohol or would have reduced Fehling's Solution before in- 
version had they been present. The monosaccharides all have the power of 
reducing Fehling's Solution directly. Since no such reduction took place, 
we feel justified in concluding that none of them were present. The iodine 
test (blue coloration of the dried residue from water extract) for soluble 
starch was negative. 

It will be shown later what quantities of the hemicelluloses were 
present. 

Dextrins have specific rotations from +195° to +215°, while dextrose 
has one of +52.5°. Hence, our dextrin estimate of 6.5 per cent, which had a 
direct reading of +12.9° and an invert one of +1.2° V. This, figured to 
normal conditions, is equal to 7.5° and shows that the carbohydrates of the 
water extract are for the most part dextrin, vegetable gums and mucilages. 

MALT DIGESTION 

The residue from the cold water extraction, which hoav weighed 13.15 
grams, was digested with freshly prepared MALT EXTRACT for two ninety 
minute periods as is the custom. The solution was then hydrolized and 



295 

aliquots reduced and the results figured to the equivalent of starch, and a 
percentage of 0.54 of starch found. The residue from the malt material was 
then dried r.nd weighed, weighing 12.22 grams. 

OXE PEE CEXT HC1 EXTRACT 

Half of the ma": extracted residue was boiled with a one per cent solu- 
tion of hydrochloric acid for one hour under a reflux condenser. Copper 
reduction determinations were made on aliquots of the extract, and cal- 
culated from the cuprous oxide to a dextrose equivalent. The results were 
6.42 per cent and 6.5S per cent respectively. This gives us an average of 
6.5 per cent for the hydrochloric acid extract by this method. 

To get further evidence as to the amount of copper reducing substan 
and to gain definite data concerning their character, determinations of pen- 
lan and galactan were made. The pentosans were determined according to 
the official method (42). 

One-fourth of the malt extracted residue yielded .1995 grams of pen- 
tosans for the aliquot. This is equivalent to 3.99 per cent of the original 
material. 

The galactans were determined according to the official method 1 42 
The remaining fourth of the malt extracted residue yielded 0.1260 grams of 
galactan. This is 2.52 per cent of the original material. 

By adding the percentages of the pentosans (3.99) and the galactan 

2.52), we get 6.51 per cent for the sum of the two. In order to determine 

how this sum compares to the results of the copper reduction method, we 

calculated the copper reduction results in terms of pentosans and galactans 

The relation of the pentosans and galactans to glucose is (10): 

(a) = 1.032 

arabinose 

: »se 

(b) = 0.898 

galactose 

The relation of the pentosans and galactans to the sum of the two is 
8/13 and 5/13 TP S pectively. 

(c) 8/13 of the copper reduction. 6.5 = 4. 

(d) 5 13 of the copper reduction. 6.5 = 2.5 

Substituting and transposing in the formulas (a) and (b) respectively, 

*, (c) 

= 3.SS Pentosans equivalent. 

1.032 
2.5, (b) 

= 2.77 Galactans equivalent. 

>.595 (d) 
3.88 — 2.77 = 6.65, the percentage of copper reduction products calculated 
to the proper pentosan — galactan equivalent. This very nearly checks with 
the 6.51 per cent, the sum of the pentosan and galactan determinations. 



296 

Sodium Hydroxide Extract 

The hydrochloric acid residue which now weighed 3.255 grams was boiled 
for thirty minutes with sodium hydroxide 1.25 per cent. The filtrate was 
neutralized, clarified and hydrolized. The reduction tests yielded no cuprous 
oxide. The residue was now dried and weighed, amounting to 0.6 grams. 

True Cellulose from the Chlorinated Residue 

The sodium hydroxide residue was moistened with water; treated with 
chlorine gas for one hour; washed with water; boiled in a solution of 2 per 
cent sodium sulfite and 0.2 per cent sodium hydroxide; washed, and dried. 
The residue, weighing .48 grams, was estimated on the basis of the original 
material and amounted to 4.8 per cent true cellulose. 

Waxes, Resins, Tannins, Color Substance, etc. 

The sum of the carbohydrates and fiber as determined in the above de- 
scribed fractions amounts to 24.70 per cent. Deducting this from the 34.22 
per cent of nitrogen-free extract, found in the original meal, leaves a re- 
mainder of 9.58 per cent. From the 95 per cent alcohol extract, where we 
would expect to find the waxes, resins, etc., we obtained by difference, 7.50 
per cent. The difference of 2.08 per cent, if distributed among the other ten 
determinations, would give on an average of 0.2 per cent shortage in each 
case. This might reasonably come within the range of experimental error, 
and so we searched no farther for substances in any other than the 95% al- 
cohol extract. 

Some general qualitative methods were applied on the 95% alcohol ex- 
tracts as we obtained them on a much larger scale than we did in the above 
experiments. (See figure on following page.) Aliquots of the extract were 
divided into two divisions by means of basic lead acetate as above de- 
scribed, and the tests made on each division. Tests for resins and tannins, 
in the portion soluble in water and not precipitated by lead acetate, were 
all negative. Tests for resins and tannins in the fraction insoluble in water 
and precipitated by lead acetate were all positive. 

Taking for granted that the small amount of color substances made no 
difference as far as nutritive value is concerned, no effort was made to deter- 
mine these quantitatively. The tests for tannins were so faint in each case 
that we decided to defer the quantitative determinations for the bran and 
the meal, as we expected later to study them separately. 

For the determination of the resins, we use the official method as applied 
to vanilla extracts (42), excepting that we weighed the precipitate made by 
the acid (HC1) on the caustic potash solution. For an aliquot representing 
5 grams of the original substance, the dried residue weighed .0355 grams. 
This is 0.71 per cent of the soy meal used. The behavior of the remainder 
of the material in the previous processes (Insoluble in benzine, soluble in 
alcohol, insoluble in water, etc.) indicated that it is made up of vegetable 
waxes, and by difference it amounts to 6.79 per cent. 



297 



Cork 



600 co 




t J /W/'i 

Percolator / / / ' ' 

(Glass) 



Apparatus for extracting meal with 95 per cent alcohol. 

Summary Table of the Results 

Hot 95 per cent alcohol extract 

Soluble in water and not precipitated by lead acetate. 

Invert sugar 0.0€ 

Sucrose - - - — 3.01 

Eaffinose - - 0.47 

Insoluble in water and precipitated by lead acetate. 

Pentosans - 0.90 

Organic acids (as citric) 1.60 

"Waxes, color principals etc... 9.52* 

Cold water extract 

Reducing matter after hydrolysis calculated as dextrin 

(including .6% pentosan, and 0.65% galactans).... 6.65 



*The difference between the above determined amounts of various 
carbohydrates, fiber, etc. and the 34.22 per cent 1ST free extract as determined 
in the meal H. 



298 

Malt extract 

Starch 0.54 

One per cent hydrochloric acid extract 

Galactans 2.52%, Pentosans 3.99% 6.65 

One and twenty-five hundredths per cent NaOH extract 

Reducing sugars 0.00 

Chlorinated residue or true cellulose , 4.80 

Digestibility of the Nitrogen Free Contents 

In this experiment the soy bean meal was prepared as a porridge by 
cooking for five hours in a double boiler. This sample of meal contained 
some grit but not enough to increase the ash content greatly. 

It had the following general composition: 

Per Cent 

Moisture 4.17 

Ash 5.80 

Protein 49.31 

Crude fiber 5.10 

Fat - 6.50 

Nitrogen-free extract 29.12 

Tke diet for the three-day period contained the following, approximately 
one-third being eaten each day: 

N-frec 
Protein Fat Ext. 

Grams grams grams grams Calories 

Milk 2,000 70 80 94 1,376 

Butter 150 127.5 1,147 

Cane Sugar 300 300 1,200 

Soy bean meal 370 182 24 108 1,375 

Total 2,750 252 231.5 502 5,098 

Per day 917 84 77.2 167 1,699 

The fecal residue from the above food weighed 224 grams moist and 
58.1 grams air dry, and contained the following: 

Per cent Grams 

Moisture 4.40 2.56 

Ash 20.64 11.19 

Protein 39.90 23.20 

Crude fiber 7.00 4.06 

Fat - -... 18.96 11.00 

INT-free extract 9.00 5.22 

Determination of the Carbohydrates of the Feces from a Diet on the 

Above Sample of Soy Meal 

The methods used in these determinations were the same as those used 
in the bean sample. 



299 

The direct polarization of the 95 per cent alcohol solution was — 2.34°, 
and the invert reading was 0. Copper reduction of the solution before and 
after inversion amounted to nothing worth taking into account. This 
showed no sucrose nor raffinose. In the light of this we assumed that the 
— 2.34 direct polarization was due to a small amount of cholesterol which, 
by hydrolysis, was changed to an organic acid which gave the reading 
after inversion (2). 

Finding no sucrose nor starches to interfere, we determined the pento- 
sans and galactans on the original substances without making the various 

extractions. 

Tabulation 

Hot 95 per cent alcohol extract. Per cent 

Organic acids as citric acid 2.12 

Waxes, color, etc 3.60 

Invert sugars 0.04 

Sucrose 0.00 

Eaffinose 0.00 

Cold Water Extract. 

Soluble starch 0.00 

Eeducing matter (calculated as dextrose) 0.37 

Malt Extract. 

Starch 0.00 

One per cent hydrochloric acid extract. 

Pentosans and galactans on original unextracted material 

Pentosans 2.67 

Galactans 0.80 

One and twenty-five hundredths per cent sodium hydrate 
extract. 

Eeducing sugars 0.00 

True celulose 6.40 

Digestibility of the Materials in the Nitrogen Free Contents 

The amount of invert Sugar in the meal was small. It was relatively 
larger in the feces than in the diet. Since there is a possibility of invert 
sugar coming into the feces from other sources than from ingested food, it 
would hardly seem worth while to make any calculations as to digestibility 
in this case. 

We obtained no evidence of sucrose in the feces, which would show 
that the sucrose of the meal is perfectly digestible. The fact that we got 
no evidence of the presence of raffinose in the feces would not necessarily 
prove the same in this case. The splitting off of the fructose, with dilute 
hydrochloric which we might expect to be complete in the stomach diges- 
tion, would leave melibiose, a reducing sugar that would reduce the Fehling 
Solution before inversion, and the .amount would show up in the 0.04 per cent 
of reducing sugar. The 0.04 per cent, if all considered from this source, 
would indicate a high digestibility factor for the melibiose. The fact that 
0.04 per cent comes well within the range of experimental error in digesti- 
bility experiments would argue that the raffinose has a high digestibility 
factor in this case. 



300 

Our tables show 2.12 per cent of organic acids. This equals 1.23 grams 
in the feces. They show 1.60 per cent in the meal, which equals 5.90 
grams. These figures give a digestibility factor of 80 per cent for the 
organic acids. This is without metabolic correction. We found 2 per cent 
organic acids in the base ration feces. Taking this from the 2.12 per cent 
in this case and estimating the digestibility with the 0.12 per cent that is 
left, we get a digestibility factor of 99 per cent for the organic acids. 
This is with metabolic corrections. 

The waxes, etc. were determined by difference in case of the meal and 
also the feces. So the chances for error in the determination are multiplied! 
by as many times as we have other determination, which amount to at 
least eight. Then, the basis on which we estimated them by difference 
(the Nitrogen free extract in case of the original meal and feces) was in 
each case found by difference. So the chances for error here were multi- 
plied by four. With so many chances for error in the determination of the 
waxes, and so many in the determination of the basis on which we should 
estimate the percentage of digestibility of them, we would consider it un- 
fair to use the figures in the tables in undertaking this. But, since the 
figures would give us a factor of 94, and no other factors seem to be robbed 
by it, we would be safe in saying that the waxes, etc. have a high digesti- 
bility. 

Digestibility of the Materials in the Cold Water and Malt Extracts 

In the meal we found all the reducing matter after hydrolysis to amount 
to 6.65 per cent of the original. Six-tenths of a per cent of this was found 
to be pentosans. Sixty-five hundredths of a per cent was found to be gal- 
actans. That left 5.4 per cent to be reckoned as dextrins. In the feces 
we found all of the reducing matter after hydrolysis to amount to 0.37 
per cent. We did not undertake to determine the pentosans and galactans 
included in this reducing matter, for we saw that it would make a difference 
of only a few tenths of a per cent above 99 for the factor of digestibility 
of the dextrins. 

Since we found no trace of starch in the feces, we concluded that what 
little starch there was in the meal was completely digested. This is what 
we would expect of any starch so thoroly cooked as this had been. 

Digestibility of the Pentosans, Galactans and True Cellulose 

Adding together the percentages of pentosans found in the different 
extracts of the bean meal, we have 5.49 per cent in the original meal. What 
we determined as pentosans in the feces amounted to 2.67 per cent. Using 
these figures in estimating the digestibility, we get 92.8 per cent. Since the 
2.67 per cent was obtained from the feces without making any previous ex- 
tractions, we thought it fair to make the same determination on the feces 
of the basal diet. We found in that 0.62 per cent. Making correction for 
this we get a factor of 94.2 per cent. 

All the galactans of the meal amount to 3.17 per cent of the original 
meal. All the galactans of the feces amount to 0.8 per cent. Using these 
figures in the estimation of the digestibility of these carbohydrates we get a 
factor of 96.2 per cent. 



301 

The chlorinated residue or true eelluiose of the meal equals 4.8 per cent 
or 17.7 gTams. That of the feces equals 6.4 per cent or 3.7 grams. Using 
these figures in estimating the digestibility we get a factor of 79 per cent. 
This seems like a high figure for the digestibility of any cellulose. We 
realize that there are some chances for error in -this determination, but our 
figures cannot be far from correct in these cases for we notice that the 4.8 
per cent in this estimation is only a 0.3 less than the 5.1 determined in the 
original meal by the official method. There was but six-tenths difference in 
the two methods used in the feces. 

MILLING OF THE SOY BE AX 
Composition of Parts 

For several years the nutritive value of wheat bran and patent wheat 
dour, when considered separately has furnished an interesting and practical 
study. In JS79 Eubner (52) showed that the nutritive value of wheat bread 
becomes lower as the bran content increases. In 1S90 Wicks (62) found by 
experiments with undecorticated wheat flour and decorticated wheat flour 
that the bread of the decorticated wheat flour was more thoroly uti ized 
than that of the undecorticated. Woods (64) has found by similar studies 
that the digestibility factor for standard patent flour was: Protein 88.6 per 
eext and carbohydrates 97.7 per cent. He found the factors for graham 
flour: Protein 74.9 per cent and for carbohydrates S9.2 per cent. From these 
figures we would have to conclude that the wheat bran is hardly at all di- 
gestible by man. 

As for other materials than wheat not so many offer the possibilities 
of separation into bran and pure flour or meai. and not so many appear to 
have been studied in this regard. Brionx <[S) compares the nutritive value 
of ground peanut shells and peanut bran. He finds peanut bran much less 
digestible than peanut meal, but much better than peanut shells. He. finds 
that when the shells and bran are mixed in different proportioas that the 
shells depreciate the nutritive value of the bran very much. His experiments 
were performed on cattle, but the comparison serves to give us am idea of 
what might be the case with man. 

Fuchs I s says that there is in peanut bran 14 — 17 per cent protein and 
14 — 18 per tent fat. The shucks contain less protein (3 — 6%) and less fat 
p > — 7%) and are 70 per cent digestible. He thinks the mixture would mak- 
a good cattle feed. 

Accepting this and recalling the fact that the navy bean bran is so 
indigestible and is responsible for fermentation and discomforting gas in 
the digestive system, we were led to the effort to separate the bran and the 
meal of the soy bear and make determinations of the nutritive value of each 
taken separately. We soon found that by the slow and tedious process of 
peeling the bran off the bean with an ordinary knife, we could make a com- 
plete separation. But, on account of the process being so tedious, we did this 
for only a limited number of beans of average size in order to determine 
the percentage of bran on the bean. 

When the separation was made we found the bran to constitute S^c of 



302 

the whole bean, the remainder being cotyledon and germ. We found that 
we could easily with the same means separate the germs and determine their 
percentage. We found the germ to constitute 1% per cent. 

We found in this process that the bran did not adhere very tightly to 
the cotyledon, and we planned to carry on the process on a larger scale with 
mills simiar to those used for wheat. By courtesy of Farm Crops Depart- 
ment of The Ohio State University, we obtained access to a set of small 
flour mills of the roller type, one of coarse adjustment and one of fine. With 
these we milled a considerable portion of the beans. We passed the beans 
thru the coarse rollers twice, then sifted thru a coarse sieve. This separated 
most of the bran, having in it a small amount of the cotyledonous material; 
Most of the meal went thru the sieve and contained some of the bran. Then, 
the first bran was passed thru the finer rovers and sifted thru the same 
coarse sieve, and that which passed thru the sieve was put with the first 
meal. Then, all of the meal was passed thru the finer rollers twice and 
sifted thru a line sieve. That which did not pass thru the fine sieve was 
placed aside as middlings. We used only the first bran and the last meal in 
the following experiments. 

The bran consisted of very large flakes. We had fco grind it thru a burr 
mill three times before it would pass thru a twenty mesh sieve. The meal 
was finer than necessary to pass thru the sieve. 

The meal had the following composition: 

Per cent 

Moisture 8.23 

Ash 4.60 

Fat 18.01 

Protein : 40.99 

Crude fiber 1.70 

Nitrogen-free extract 26.47 

The bran had the following composition: 

Per cent 

Moisture 8.46 

Ash 4.42 

Fat 1.50 

Protein .- : 5.81 

Crude fiber 37.00 

N-free extract 42.81 

Digestibility of the Bran 

In the digestibility experiment, the subject was a man thirty-eight years 
old, weighing 150 pounds, 5 ft. 8 inches high, enjoying good health and 
working at the ordinary laboratory routine. The diet consisted of the fol- 
lowing, divided equally among the three days of the diet period: 

3000 cc. whole milk, 4% fat, 3.5% protein, and 4.5% carbohydrates. 
207 grams butter fat 



303 

200 grams cane sugar 

100 grams potato starch, pure, well cooked 

100 grams soy bean bran cooked for one-half hour in boiling water into 
a thin mush. 

Subject felt no ill effects whatever thruout the entire period of one day 
previous to diet, the three days' diet period and one day following. Feces 
were regular every morning, but were slightly hard. The feces of the 
three days' experimental period was marked off by a capsule of carmine 
taken with the appropriate meals, and in the moist state weighed 210 grams. 
The stools were each treated as in previous experiments, and weighed when 
air dry 60 grams. The analyses were carried out as in previous experiments. 

The composition was as follows: 

Per cent 

Moisture . ..".'. 7.31 

Ash 22.23 

Fat , , 24.11 

Protein ; ~-' 12.40 

Crude fiber 20.30 

X-free Extract 13.65 

Since the amount of protein and fat in the bran amount to so little in 
each case, we considered it not worth while to determine the digestibility of 
these constituents- of the diet. 

The carbohydrates and the crude fiber are the prominent components of 
the bran material, and so we deemed it sufficient to determine the digest- 
ibility in these two cases only. 

The Digestibility of the Nitrogen-Free Extract 

The 13.65 per cent of nitrogen free extract in the feces, or 8.1, grams 
based on the 60; diminished by the 1 per cent or 1.49 grams, based on the 
140 grams of milk sugar ingested; equals 6.79 grams, nitrogen free extract 
in the feces. This, based on the 42.81 grams of nitrogen free extract in the 
100 grams of the bran used in the diet, leaves a residue of 15.8 per cent 
and a digestibility factor of 100 — 15.8 or 84.2 per cent. This is much less 
than the digestibility factor for the nitrogen free extract of the soy bean 
as a whole, (96.9) as determined previously by us. This is due. very likely, 
to the large proportion of waxes, etc. in the bran. 

Digestibility of the Crude Fiber 

We found in the feces of the bran diet 20.3 per cent of crude fiber, 
which was 12.18 grams based on the 60 grams of the feces. There was 37 
per cent, or 37 grams of crude fiber in the 100 grams of bran in the diet. 
Using these figures, 37 as the base and 12.18 as percentage, we get 32.9 
per cent of the undigested fiber. This gives 100 — 32.9 or 77.1 per cent for 
a digestibility factor for the crude fiber. This figure seems high for a 
fiber, but it is only 2 — 4 per cent higher than we found for the fiber in our 
previous experiments on the whole meal, and 2 per cent lower than found 
for true cellulose. 



304 
Physical Effects of a Diet Solely of the Mush Made From the Bran 

! 

In order to see what would be the physical effects of a day's diet on 
the bran alone, we made three meals of 30 grams each for one day. Next 
day we were a little uncomfortable on account of a slight amount of gas 
in the bowels. We were a little weak and very hungry but not sick. The 
next day the stool was voluminous but not so very soft. The diet hart 
neither a laxative nor a constipating effect that could be noticed. 

The Calcium Oxide and the Phosphorus Pentoxide Content of the Soy 

Bran and Soy Meal 

Osborn and Mendel . (44), in the same series of experiments in which 
they determined the vitamine content of the soy bean, made some determina- 
tions as to the mineral content as related to the growth of rats. They 
found it somewhat lacking in calcium. 

In our consideration of the food value of the meal and bran separately, 
we endeavored to determine whether or not we could increase the ratio of 
calcium by making use of the meal alone as food. We made quantitative 
determinations of the Calcium Oxide (according to the Official Method) (42) 
in the bran and in the meal separately. We found the CaO of the bran to 
be 0.80% and that of the meal 0.27%. Counting the bran 8% and the meal 
92% of the whole bean, we arrived at the amount of CaO in the whole meal 
as follows: ■ , 

8/100 = ratio of bran to whole product 

92/100 = ratio of meal to whole product '' 

0.80 = per cent CaO in bran 

0.27 = per cent CaO in meal 

8/100 X 0.80 = 0.064 bran's share of the CaO 

92/100 X 0.27 = 0.248 'meal's share of the CaO 

0.064 + .248 = 0.31, the percentage of CaO in the whole meal. 

The proportions of Calcium Oxide in the meal, and the bran, are some- 
what similar to the proportions of Calcium Oxide in the wheat flour and the 
wheat bran, that of the wheat flour being about 0.025%, and that of the 
wheat bran about 0.14%. But, the amounts are much larger in the spy 
products in each case. The CaO of the soy bean taken as a whole is about 
twice as large in amount as that of the common pea, (that for the pea be- 
ing about 0.14%), and a little larger than that of the navy bean (that being 
about 0.22%), also greater than that of the cow pea, (a relative to the soy 
bean having about 0.18%) (56). 

Of the non metallic inorganic substances in a food material, the phos- 
phates are undoubtedly the most important (56). Rations, balanced accord- 
ing to nature, like milk and eggs have relatively large proportions of these. 
Many of the seeds and cereals have small quantities in relation to the 
organic food contents. Considering this, and recalling that wheat bran has 
a much larger phosphorus content than has wheat flour (56), we decided to 
make quantitative determinations of the Phosphorus Pentoxide in both the 
bran and the meal of the soy bean. By application of the Official Method 
(42) in several samples, we found the P_>0.- ( of the bran to be 0.27% and that 



305 

of the meal to be 1.52%. Following the same method of calculation for the 
P 2 0.- ( in the whole meal as we did for the Calcium Oxide, we found 1.42%, 
for the whole meal. We then found the P2O5 in the whole meal and found 
it to be only 0.04% less than the above figure. 

The removal of the bran raised the P2O5 content from 1.42%. to 1.52%, 
or an increase of 0.10%. This is not enough tc make any difference as to 
the removal of the bran, for the P2O.3 is increased only one-fifteenth of 
itself by the removal of the bran. 

The proportions of P2O5 in the soy bran to that in the soy meal is 
opposite to that in the wheat bran and the wheat flour. In the soy meal 
it is five times as great as it is in the soy bran. In the wheat flour it is 
one-fifteenth as great as it is in the wheat bran, being 20% P2O5 in the 
wheat flour while it is 3.0% in the wheat bran. This amount of P2O5 in the 
whole bean is about seven times as great as it is in the wheat flour. It is 
one-half as great again as it is in the cow pea, (1.0%) and a little greater 
than it is in the common navy bean, (1.14%) (56). 

TOXIC AND DISAGKEEABLE OR UNPALATABLE SUBSTANCES 

OF THE SOY BEAN 

Some Investigations as to the Possible Poisons 

A great many of the different leguminous seeds are poisonous. The 
castor bean and the Burma bean are noteworthy examples. It is generally 
conceded that if one could eat enough of the common navy bean raw, it 
would have a poisonous effect. A great many people parboil and discard the 
first water from the navy bean, considering it to be poisonous. Pammel (48) 
says that the Eepe Beans of the Scarlet Runner are poisonous. 

Joseph Burtt-Davy (16) describes several species of Crotalaria, a legume 
with some characteristics like the soy bean, which are poisonous to stock. 
He describes the symptoms and the results of the diseases. Watt (61) says , 
that he has known horses to die after eating the dried peas of the Lathyrus 
Sativus— 'militar'." 

Church (13) says that a paralysis has been induced in man by Muttar. 
Chestnut (12) says that Crotalaria Sagatallis L, — "Rattlebox" — a legume 
found in the Central United States, has been known to poison horses. 

Pammel (48) says that the soy bean can be fed to animals in small 
quantities only, on account of its purgative properties. He says that a loss 
of considerable number of cattle occurred in England recently, where soy 
bean cake had been used. When the soy products were fed mixed no trouble 
was caused, but when fed alone they were poisonous. 

H. C. Brill (9) says that twenty-five samples of soy beans and a large 
number of other beans were tested by the Ferric Chloride test and Jor- 
rison's test, and that the soy beans from Japan gave positive tests for 
Salicylic Acid, while Chinese, American and Philippine beans gave either 
negative or slightly positive tests. None of the soy beans gave Jorrison's 
test after they were fermented. 

A. C. Whittier (62) gives an account of trouble with soy bean hay as 
a roughage for animals. He found by extracting the hay that there was a 



306 

poison, poisonous to guinea pigs. The extract that was poisonous to the 
guinea pigs was made with a 70-80% alcohol and water solution and pre- 
cipitated with lead acetate. We are of the opinion that the above described 
poisonous effects were due to something that developed in the products on 
standing, especially when we find that Kiyohisa Yoshimma (65) found the 
three ptomaines: Inidoazolylethylamine, Tetramethylenediamine, Pentameth- 
ylenediamine in decomposed soy bean products. 

It is possible too that the small amount of poisonous substances that 
have been suspected to be present in the soy to such an extent that they 
cannot be made to constitute an entire ration for stock, would be cooked 
out as well as fermented out in the preparation of food for man. 

It has been suggested (4) that there is a slight trace of HCN in the soy 
bean meal. 

We made the following Cyanide tests to see if we could detect the 
presence of cyanide: 

Iodin solution test, negative with both bran and meal. 
Mercuric Chloride test, negative with both bran and meal. 
Gruaic Acid and Copper Sulphate test negative with both bran and meal. 
Sodium Pieratc Paper was not reddened by the gas evolved from either 
bran or meal, either before or after being treated with sulphuric 
aeid. So it seems as tho there is no HCN or cyanides of any kind 
present in the bran or the meal of the samples we tested. 
Street and Bailey (59) suggest that there might possibly be tannins 
preseat in the soy bean. We made the following tests for tannin on the 
bran amd meal separately: 

Ferric chloride gave a very little milky color, but this did not disappear 
•n heating. (This resulted the same way for both bran and meal.) 
We obtained a similar result from the whole meal. 
Alcohol solution of Thymol and concentrated sulphuric acid gave very 

slight pink with meal but no test with bran. 
Iodine in neutral solution gave negative results in case of both bran 

and meal. 
Ammonium Chloride and Ammonia gave negative results in both cases. 
Potassiumferricyanide gave slighest red with the meal, but nothing with 

the bran. 
Not being satisfied with the qualitative tests, we made the official 
quantitative tests (gravimetric) and in four cases with the meal gave an 
average of 0.004% and the bran nothing. It seems that whatever amount of 
tannin there is in the soy bean is found in the cotyledon and not in the 
bran. 

After removing the protein from the alcohol solution extracted from 
both the meal and the bran, we got a positive test for a slight trace of al- 
kaloids with each, Mercury-potassium Iodide, and Phosphotungstic Acid, and 
Phosphomolybdic Acid in both the meal and bran. Not enough alkaloids in 
either case to call for quantitative determination. 

In our tests for salicylic acid, we got negative results in case of both 
the bran and the meal. 



307 

Location and Elimination of the Disagreeable and Unpalatable Substances 

Ldke a great many other food materials the soy bean may be destined to 
undergo a period of unpopularity on account of its peculiar flavor. It 
would seem very unfortunate if a food as highly nutritious, and as free 
from harmful elements as is the soy bean, would fail to take an important 
place in our diet. But, it seems as though a good many of us are not in- 
clined to relish it in its common form. 

In most of the Japanese foods made from the soy bean the disagreeable 
flavor is avoided by the nature of the preparation made. These, for the 
most part, involve some sort of fermentation which changes the flavor en- 
tirely. The Domestic Science Department of the Ohio State University has 
carried on considerable experimentation making different preparations, com- 
binations and extractions, as well as making use of different methods of 
cooking soy bean preparations, to avoid the disagreeable flavor. Phillips, 
in a piece of work in the laboratory of the Department of Foods and Nutri- 
tion in the Ohio State University, experimented by extracting with hydro- 
chloric acid in order to remove the flavoring substance. He succeeded in ob- 
taining a product that had an excellent taste, but the hydrochloric added 
removed a great deal of the valuable food matter. 

Wishing to avoid loss of valuable food material as much as possible, we 
attempted to locate the disagreeable flavors in some physical part such as the 
bran or germ which could be removed and otherwise utilized; or in some 
chemical constituent, such as the oil or acids which might be extracted and 
used commercially. Such attempts inevitably called for many tests as to 
flavor. "We realized that the people on whom we could call to make the 
tests were working under different conditions as to exercise and diet, and 
could not be relied upon for uniform decisions. So we conceived the idea 
of obtaining a selection of small animals, keeping them under uniform 
conditions, allowing them free access to the different products; and judging 
.the tastes according to the amount the animals consumed. 

Thinking of the minute differences that might not show up with the 
various products, if we considered the consumption of each individual we 
made record of the daily consumption per gram animal. 

For our experiments we selected rats to "which to feed the different 
products, because they seem to have a very delicate sense of taste, and they 
appear to uniformly approve or disapprove of different flavors. From the 
fact that rats are found wherever man is found, and are not found else- 
where, and from the fact that they consume man's food, we would judge 
that as far as matters relating to their foods are concerned the tastes of 
rats coincide fairly well with our own. 

For the sake of comparison, in our attempts to locate the substance or 
substances responsible for the flavor of the soy bean, we treated the differ- 
ent parts and products of the navy bean the same way. In many cases 
we conducted the tests on the two side by side, feeding three rats on each 
product of the soy and navy bean for three days at a time. In the selec- 
tion of these rats for each test, we selected one a little less than half 
grown, one a little more than half grown, and one full grown. This proved 
to be a good selection, for the reason that the full grown ones appeared to 



308 

be willing and able to tide over the period of distasteful food better than 
the young and growing ones, and the very young ones appeared to be more 
sensitive to the slight disorders attending a diet which is not up to the 
standard in nutritive qualities. This further necessitated our taking into 
consideration the size of the animal and making our estimate per gram rat. 

In order that a supply of food might be before the rats all of the time 
thruout the three days and yet be in a condition to enable us to determine, 
from day tc day, how much each rat consumed, we made it into a paste. 
We used no water in the paste for it would evaporate more or less and fer- 
mentation would take place before the three-day period had passed. We 
found butter good for this purpose altho we had to use a mixture of thirty- 
three per cent in order to make the food pasty enough to stick together. 
This amount of butter was found not to interfere with the comparative 
flavors of the various products. 

We supplied each rat constantly with something in the nature of greens 
or succulent vegetables, so that the diet would not be too concentrated for 
their physical condition and so that the water soluble accessory, which 
might not be present in every diet that we gave, would not be entirely 
wanting. We found raw potato the best in this regard, not because it had 
the most of the vitamines, but because the rats would eat it better than 
other things of this kind. We numbered the six rats I, II, III, IV, V and 
VI, which numbers we maintained thruout the entire series of experiments, 
feeding each rat in a separate cage. 

The following data, altho all excepting that of Experiment I is summed 
up in average, was taken from extended notes in which were recorded the 
weight in grams of food consumed each day by each rat separately, and the 
weight of each rat at the beginning and at the end of each three day's diet 
period, and also the physical condition of each rat as best we could determine 
from external appearances as here recorded in I. 

The data here noted is followed by a series of charts which show at a 
glance the desirability of the different food products for the same six rats, 
as they were allowed to eat as much as they chose from each preparation. 
We drew our conclusions as to the relation of the flavors from the relative 
amounts corisumed by the rats. 

EXPEKIMENT I 

In the first experiment each of the six rats was fed a balanced ration 
for three days. It was known to contain everything necessary for the pro- 
motion of growth. It consisted of: casein, dextrin, salts, agar, butter fat 
and water extract of oats. Eats were known to relish this diet, and so they 
were fed on it to determine how much they would consume per day. About 
5 grams of green clover was also gliven to each rat to determine whether 
they had any inclination to depart from the balanced ration. 



309 

Wt. Grams 

Day of rat consumed Kemarks 

Rat I 1 75 6 Ate no clover 

2 7 Ate no clover 

3 77 6 Ate no clover 

Rat II 1 143 

2 

3 144 

Rat III 1 219 

2 

3 219 

Rat IV 1 L76 

2 

3 177 

Rat V 1 176 

2 

3 178 

Rat VI 1 75 

2 

3 77 

Rats averaged 0.63 grams food per gram rat per day. 

Before recording the following experiments, we found th/tt none of the 
rats would eat navy bean meal mixed with water, and they would eat 
very little of the soy bean meal so prepared. 

EXPERIMENT II. 
Soy Cake Meal 

Rats I, II, and III were fed on a diet consisting of 67 per cent soy 
cake meal, and 33 per cent butter mixed into a paste. Approximately 5 
grams of clover also were given each rat. 

Average daily consumption per gram rat, 0.038. 

Average gain in weight per rat, 0.00%. 

Condition of rats at end of three days diet period, slightly irritable. 

Rats IV, V and VI, were fed on a diet consisting of 67 per cent dif- 
ferent sample soy cake meal, and 33 per cent butter mixed to a paste. About 
5 grams of clover also were given to each rat. 

Average daily consumption per gram rat, 0.035. 

Average gain in weight per rat, 0.17%. 

Condition of rats at end of three days diet period, slightly irritable. 



8 


Ate 


no clover 


9 


Ate 


no clover 


10 


Ate 


no clover 


12 


Ate 


no clover 


12 


Ate 


no clover 


12 


Ate 


no clover 


10 


Ate 


a little clover 


11 


Ate 


no clover 


10 


Ate 


a little clover 


10 


Ate 


half clover 


10 


Ate 


no clover 


11 


Ate 


no clover 


7 


Ate 


no clover 


6 


Ate 


no clover 


6 


Ate 


no clover 



310 

EXPERIMENT III. 
Whole Soy Bean Meal and Whole Navy Meal 

Rats I, II and III were fed on a diet consisting of 67 per cent whole 
meal made from the soy bean, and 33 per cent butter, made into a paste. 
Approximately 5 grams of green alfalfa were given to each rat. 

Average daily consumption per gram rat, 0.033. 

Average gain in weight per rat, 0.25%. 

Condition of rats at end of three days diet period, irritable and hungry. 

Rats IV, V and VI were fed on a diet consisting of 67 per cent whole 
meal made from navy beans, and 33 per cent butter well mixed into a paste. 
About 5 grams alfalfa to each rat. 

Average daily consumption per gram rat, 0.021. 

Average gain in weight per rat, 0.00%. 

Condition of rats at end of three days diet period, very irritable. 

EXPERIMENT IV. 
Soy and Navy Bean Bran-Free Meal 

Rats I, II and III were fed on a diet consisting of 67 per cent pure 
navy bean meal, bran free, and 33 per cent butter, mixed into a paste. 
Approximately 5 grams of raw potato were given to each rat. 

Average daily consumption per gram rat, 0.022. 

Average gain in weight per rat, 0.08%. 

Condition of rats at end of three days diet period, very irritable. 

Rats IV, V and VI were fed on a diet consisting of 67 per cent pure soy 
bean meal, bran free, and 33 per cent butter, mixed into a paste Approx- 
imately 5 grams of raw potato were given to each rat. 

Average daily consumption per gram rat, 0.030. 

Average gain in weight per rat, 0.25%. 

Condition of rats at end of three days diet period, very irritable. 

EXPERIMENT V. 
Soy and Navy Bean Bran 

Rats I, II and III were fed on a dtiet consisting of 67 per cent navy 
bean bran, separated from the cotyledons, and 33 per cent butter, mixed 
into a paste. Raw potato was given as in previous experiments. 

Average daily consumption per gram rat, 0.036. 

Average gain in weight per rat, 0.25%. 

Condition of rats at end of three days diet period, somewhat bloated, 
feces soft. 

Rats IV, V and VI were fed on a diet consisting of 67 per cent soy 
bean bran and 33 per cent butter, mixed into a paste. Raw potato was 
given as in previous experiments. 

Average daily consumption per gram rat, 0.043. 

Average gain in weight per rat, 0.33%. 

Condition of rats at end of three days diet period, feces soft. 



311 

EXPERIMENT VI. 

Benzine Extracted Soy and Navy Bean Meal 

Eats I, II, and HI, fed on a diet consisting of 67 per cent navy bean 
meal, benzine extracted, and 33 per cent butter, mixed to a paste. Raw 
potato "was given as in previous experiments. 

Average daily consumption per gram rat, 0.026. 

Average gain in weight per rat, 0.00. 

Condition of rats at end of three days diet period, feces small and hard. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent soy 
bean meal, benzine extracted, and 33 per cent butter, mixed to a paste. 
Eaw potato was given as in previous experiments. 

Average daily consumption per gram rat, 0.031. 

Average gain in weight per rat, 0.17%. 

Condition of rats at end of three days diet period, feces small and hard 

EXPEEEtfEXT VII. 
Alcohol Extracted Soy and Navy Meal 

Eats I, H, and IH, were fed on a diet consisting of 67 per cent ether 
and alcohol extracted soy bean meal and 33 per cent butter, mixed into a 
paste. Eaw potato was given as in previous experiments. 

Average daily consumption per gram rat, 0.035. 

Average gain in weight per rat, 0.00. 

Condition of rats at end of three days diet period, normal. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent ether 
and alcohol extracted navy bean meal and 33 per cent butter mixed to a 
paste. Eaw potato as in previous experiments. 

Average daily consumption per gram rat, 0.040. 

Average gain in weight per rat, 0.08. 

Condition of rats at end of three days diet period, normal. 

EXPEEIMEXT Vm. 
Balanced Ration 

For the purpose of finding out how much the rats would eat of a diet 
they liked, and which was nutritious, we fed all six of the rats on a diet 
consisting of: 

Corn meal 66 per cent, soy meal 22 per cent, and alfalfa leaf meal 12 
per cent. Then on the whole mixture, 67 per cent and 33 per cent butter 
mixed into a paste. Eaw potato was given each rat as in previous ex- 
periments. 

0.058 grams of this ration, per gram rat per day, were consumed by 
the six rats during the three days' diet, with an average gain of 0.44 
per cent per rat. 

All rats were in normal condition in every respect, so far as we could 
determine. 



312 

EXPEEIMENT VIII b. 
Cooked Soy and Navy Meals 

In the following experiments we fed rats I, II, and III, on whole soy 
meal that had been cooked in boiling water for four hours. This means of 
treatment raised the average daily consumption from 0.033 to 0.037 per 
gram rat. 

When the navy bean was so treated, rats IV, V and VI, increased their 
average daily consumption from 0.021 grams to 0.045 grams per gram rat. 

EXPEEIMENT IX. 
16% Soy and 2% Navy Bean Oils 

Rats I, II, and III, were fed on a diet consisting of 67 per cent of bal- 
anced ration as in experiment VIII, 33 per cent of butter and to this 16 
per cent of soy bean oil. Eaw potato was given as in previous experiments. 

Average daily consumption per gram rat, 0.040. 

Average gain in weight per rat, 0.17%. 

Condition of rats at end of three days diet period, rat II sick, others 
normal. 

Eats TV, V and VI, fed on a diet consisting of same as above, except- 
ing all the navy bean oil that was extracted from 50 grams of meal was put 
in 50 grams of the balanced ration as above. 

Average daily consumption per gram rat, 0.058. 

Average gain in weight per rat, 0.56%. 

Condition of rats at end of three days diet period, normal. 

EXPEEIMENT X. 
4% Soy and 4% Navy Oils 

Eats I, II, and III, were fed on a diet consisting of 67 per cent of 
balanced ration as in Experiment VIII, 33 per cent of butter and to this 
4 per cent of soy bean oil. Eaw potato was given as in previous experiments. 

Average daily consumption per gram rat, 0.050. 

Average gain in weight per rat, 0.25%. 

Condition of rats at end of three days diet period, normal. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent of bal- 
anced ration as in experiment VIII, 33 per cent butter and to this 4 per 
cent of navy bean oil. Twice as much as in previous experiments. 

Average daily consumption per gram rat, 0.049. 

Average gain in weight per rat, 0.35%. 

Condition of rats at the end of three days diet period, normal. 

EXPEEIMENT XI. 
Alcohol Extracted Sugars of Soy and Navy Beans 

Eats I, II and III, were fed on a ration consisting of 67 per cent bal- 
anced ration as in experiment VIII, 33 per cent butter and the alcohol ex- 
tracted sugar that came from the soy bean, in same percentage as they 
came out of the soy bean. 

Average daily consumption per gram rat, 0.055. 



313 

Average gain in weight per rat, 0.48%. 

Condition of rats at end of three days diet period, normal. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent bal- 
anced ration as in experiment VIII, and 33 per cent butter and the alcohol 
extracted sugar that came from the navy bean, in same percentage as they 
came out of the navy bean. 

Average daily consumption per gram rat, 0.046. 

Average gain in weight per rat, 0.40%. 

Condition of rats at end of three days diet period, normal. 

EXPEEIMENT XII. 
Organic Acids of Soy and Navy Beans 

Eats I, II, and III, were fed on a ration consisting of 67 per cent 
balanced ration as in previous experiments, 33 per cent butter and the or- 
ganic acids that eame out of the bran. 

Average daily consumption per gram rat, 0.044. 

Average gain in weight per rat, 0.17%. 

Condition of rats at end of three days diet period, restless. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent bal- 
anced ration as in previous experiment and 33 per cent butter and the or- 
ganic acids that came from the navy bean, in same percentage as they 
came out of the bean. 

Average daily consumption per gram rat, 0.045. 

Average gain in weight per rat, 0.08%. 

Condition of rats at end of three days diet period, restless. 

EXPEEIMENT XIII. 
Waxes from Soy and Navy Bean 

Eats I, II and III, were fed on a diet consisting of 67 per cent balanced 
ration as in previous experiments, 33 per cent butter, and the waxes, etc., 
that came from the soy bean, in the same percentage as they eame from 
the bean. 

Average daily consumption per gram rat, ^0.045. 

Average gain in weight per rat, 0.17%. 

Condition of rats at end of three days diet period, normal. 

Eats IV, V and VI, were fed on a diet consisting of 67 per cent bal- 
anced ration as in previous experiments, 33 per cent butter, and waxes, etc., 
that came from the navy bean, in the same percentage as they came out. 

Average daily consumption per gram rat, 0.048. 

Average gain in weight per rat, 0.17%. 

Condition of rats at the end of three days diet period, normal. 

EXPEEIMENT XIV. 
Water Extracted Soy and Navy Bean 

Eats I, II and III, were fed on a diet consisting of 67 per cent water 
extracted soy meal and 33 per cent butter. 

Average daily consumption per gram rat, 0.037. 
Average gain in weight per rat, 0.08%. 



314 

Condition of rats at end of three days diet period, normal. 
Eats IV, V and VI, were fed on a diet consisting of 67 per cent water 
extracted navy bean meal and 35 per cent butter. 
Average daily consumption per gram rat, 0.035. 
Average gain in weight per rat, 0.08%. 
Condition of rats at end of three days diet period, slightly irritable. 

EXPEKIMENT XV. 
Water Extract of Soy and Navy Beans 

Eats I, II and III were fed on a diet consisting of 67 per cent balanced 
ration as in Experiment VIII, 33 per cent butter, and the water extract that 
came from the bean. 

Average daily consumption per gram rat, 0.056. 

Average gain in weight per rat, 0.35%. 

Condition of rats at end of three days diet period, normal. 

Eats IV, V and VI fed on a diet consisting of 67 per cent balanced ra- 
tion as in Experiment VIII, 33 per cent butter, and the water extracted 
syrup that came from the navy bean, in same percentage as it came out. 

Average daily consumption per gram rat, 0.060. 

Average gain in weight per rat, 0.50%. 

Condition of rats at end of three days diet period, normal. 

EXPEEIMENT XVI. 
Cooked Soy Oil and Steam Distillate from Soy Meal 

Eats I, II and III were fed on a diet consisting of 67 per cent cooked 
soy bean oil, and extracted meal, in same proportions as in the original, and 
33 per cent butter. 

Average daily consumption per gram rat, 0.040. 

Average gain in weight per rat, 0.08%. 

Condition of rats at end of three days diet period, restless. 

Eats IV, V and VI were fed on a diet consisting of the steam distillate 
from the soy meal put in same quantity of balanced ration as meal from 
which it whs distilled, and butter in ratio of 67 to 33. 

Average daily consumption per gram rat, 0.056. 

Average gain in weight per rat, 0.41%. 

Condition of rats at the end of three days diet period, normal. 

EXPEEIMENT XVII. 

In this experiment the six rats were fed on a diet of the same balanced 
ration used in Experiment VIII, excepting that it was barely moistened with 
benzine and spread thinly over paper and placed in a slight current of air, 
and dried for twenty-four hours. The daily consumption was recorded and 
found to be somewhat like that of Experiment VI, increasing sHghtly as the 
days progressed. On account of their eating more of the balanced ration 
than of the soy or navy meal we could notice better the daily increase. 

The da51y consumption for all the rats averaged per gram rat 0.046, as 
against 0.058 in the balanced ration, which indicated that the benzine had 



315 

not completely evaporated away. This showed us what allowance to make 
over the average daily consumption of the benzine extracted meals in Ex- 
periment VI. 

EXPERIMENT XVIII. 

In this experiment all of the six rats were fed on the same diet as in 
Experiment XVII, excepting that alcohol was used instead of benzine. The 
daily consumption was found to be somewhat like that of Experiment VII, 
only in this experiment we had to figure out the average for each day in or- 
der to tell that they increased as the days p-rogressed. 

The daily consumption for all of the rats in this experiment averaged 
per gram rat 0.051 as against 0.058 when the balanced ration was not so 
treated, which indicated that the alcohol had not completely evaporated 
away, and showed what allowance should be made for this in Experiment 
VII. It showed also that the alcohol was not quite as distasteful to the rats 
as was benzJne. 

EXPERIMENT XIX. 

In this experiment we extracted the soy meal for fifteen minutes with 
a ten per cent solution of sodium bicarbonate. Some of the household 
preparations are made this way just before cooking, with the idea that the 
flavor is improved, and that a bitter poisonous substance is removed. The 
rats made a very slight difference in their daily consumption. The average 
was 0.038. That of the unextracted meal was 0.033. 

When the navy bean meal was treated the same way as the soy meal 
the daily consumption was increased from 0.021 to 0.027, a little greater 
proportion than in the soy product. In order to carry the test further, we 
evaporated the extract and put solids back into the same balanced ration as 
we did with the extracts in previous experiments. 

EXPERIMENT XX. 

Rats I, II and III were fed on a diet of balanced ration with the soda 
extract added in the same proportion in which it had been extracted from 
the soy bean, together with solid sodium carbonate that had to go with it, 
which was about five grams of the carbonate in fifty grams of the meal. 
This lowered the daily average consumption from 0.058 for the balanced 
ration to 0.054 for the same ration with the extract and salt in it. 

Rats TV, V and VI were fed on a diet like that above only navy bean 
soda extract was used. The extract and solid soda in this case lowered the 
average consumption from 0.058 to 0.054. The extracts added to the bal- 
anced ration did not lower its consumption as much as their removal from 
the meals raised it. 



316 



Chart I represents a summarized comparison of the results of a few of 
the diet experiments with those of the first balanced ration experiment, and 
also with those of the second balanced ration experiment which is No. VIII 
in the list. 

The full extent of the- bars, in all three of the following charts, which 
measures 63 mm., represents the 0.063 grams, daily consumption per gram 
rat of the first balanced ration, (Exp. I). The dark portion of each bar 
represents the daily consumption of the experimental diet, and the half 
dark portion the approximate amount of clover or succulent vegetable 
material consumed. 

The half dark portion is not continued in Chart II or Chart III for 
the reason that we noted no definite relation existing between this and 
the dark portion in Chart I. 



CHART I 



Exp. No. 



8 44% corn, 15% soy, 33% butter, 8% alfalfa 



2. Soy cake meal containing 3% fat. 



Soy cake meal containing 6% fat. 



3. Whole soy bean meal. 



Whole navy bean meal. 



4. Pure soy meal, bran separated. 



Pure navy meal, bran separated. 



5. Soy bean bran. 




9. Same as 8, with 16% soy oil added. 



Same as 8 with 2% navy oil added. 



10. Same as 8 with 4% soy oil added. 



Same as 8 with 4% navy oil added. 



leaf meal. 



317 



Chart II represents a summarized comparison of the results of a few of 
the diet experiments with those of the first balanced ration, and also with 
those of the balanced ration moistened with benzine, (Exp. XII), to which 
we wish to make especial comparisons of the diets on materials which were 
products of the benzine extraction. 

In this chart aie also represented the results of Exp. XIII on the bal- 
anced ration, moistened with alcohol; followed by experiments on diets of 
the products of alcohol extraction. 

The balanced ration experiment (Exp. Xo. VIII) is also represented in 
the same- chart for the purpose of comparing it with the standards repre- 
sented by Xo. XII and XIII. 



CHART II. 



Exp. X T o. 



12. Balanced ration moistened with benzine and 



6. Soy meal, bezine extracted. 



dried. 



Xavy meal, benzine extracted. 



16. Soy meal, benzine extracted, cooked soy oil 



13. Balanced ration moistened with alcohol and dried. 



7. Benzine and alcohol extracted sov meal. 



Benzine and alcohol extracted navv meal. 



9. Balanced ration as in 8 




11. As in S and alcohol extracted carbohvdrates 



As in 8 and alcohol extract and carbohvdrates from navv bean 



12. As in 8 and organic acids from soy bean. 



As in 8 and organic acid from navy bean. 



13. As in 8 and waxes from sov bean. 



As in 8 and waxes from navv bean. 



eplaced. 



from sov bean. 



318 



Chart III is introduced by a bar representing the results of the experi- 
ment with whole soy bean meal, and followed up by results from various 
extracted and extraction products. 

A bar representing the results of the balanced ration No. VIII is again 
inserted about the middle of this chart and followed by results from the ad- 
dition of various extracted materials to the balanced ration. 

Results from experiments on the cooked products are also represented 
on this chart. 



CHAET III. 



Exp. No. 



3a. Whole soy bean meal. 



14. Water extracted soy meal. 



Water extracted navy meal. 



19. Soy meal extracted with 10% sol. soda. 



Navy meal extracted with 10% sol. soda. 



8. Balanced ration as in 8. 



15. Balanced ration and water extracted material 



Balanced ration and water extracted material from navy meal 



20. Balanced ration and soda extracted material 



Balanced ration and soda extracted material 



3b Whole soy meal boiled four hours. 



Whole navy meal boiled four hours. 



16b. Balanced ration and steam distillate from soy meal. 



from soy meal. 



from soy meal. 



from navy meal. 



319 

A Steam Distillation for the Purpose of Separating the Objectionable Flavor 

Five hundred grams of the whole meal were moistened with water and 
distilled with steam for an hour. The distillate was caught in four differ- 
ent equal portions about 50 cc. each. The last two portions had no notice- 
able odor. The second portion had the least bit of a beany odor. The 
residue in the flask still retained the characteristic soy bean odor, and had 
the characteristic taste of the cooked soy bean meal. 

The first portion of the distillate standing in an uncorked flask over 
night lost most of its beany flavor. It lost the beany flavor entirely by 
standing twenty-four hours. The second portion of the distillate had lost 
its beany odor entirely by standing in an uncorked flask over night. 

Another steam distillation of another five hundred grams was made 
for fifteen minutes. The distillate was corked tightly, and each morning 
one-third of dt was removed and mixed with the balanced ration referred 
to above and fed to the rats in the same proportion in which it came from 
the meal. There was no appreciable difference in the way the rats ate 
this and the way they ate the balanced ration. The beany odor disappeared 
from the mixture in a few hours. 

Another steam distillation of another five hundred gram portion of the 
meal was made for fifteen minutes. The distillate was immediately shaken 
with ether, the ether layer separated and the ether evaporated. There was 
not enough residue left for analysis, nor would we, in our judgment, have 
secured enough in ten distillations. 

DISCUSSION OF EESULTS 

The question naturally arises: Why have the results from the foregoing 
experiments in the determination of the digestibility of the proteins of the 
soy cake meal been in both cases higher, (p. 291), than the results obtained 
by Mendel and Fine (35) and others, for the proteins of the whole soy 
bean meal? Obviously it is the same protein in both cases, yielding on 
digestion the same amino acids. 

First: The most important consideration must be given to the fact 
that the protein of the soy cake meal is not^ accompanied by nearly so 
large an amount of soy bean oil as is that of the whole bean meal. There 
is the possibility that the larger amount of oil in the whole bean meal con- 
tained sufficient amounts of some constituent to slightly inhibit certain 
enzymic action or to be responsible for premature defecations, — conditions 
which would result in lower digestibility factors for the whole bean meal 
(37) (38). 

Second: If we had any correct method of estimating what, these 
authors' results would have been had they made the same sort of metabolic 
allowances; or of determining what our results would have been had we 
not been compelled to make such allowances, on account of the standards 
for the milk and the flour used, our results might not have been any 
higher than theirs. We would rather attach more 'important to the first 
reason, and consider the point in favor of the soy cake meal. 

The almost complete digestibility of the vegetable gums and dextrins 
of the soy bean (p. 300) would lead us to the conclusion that they are not 



320 

very complex in their structure, and, if there is such a thing as one kind of 
vegetable gums being simpler in structure and nearer to the dextrose than 
is another, the vegetable gums of the soy bean belong to that class. The 
fact that some of the earlier experimenters estimated that there existed 
in the soy bean from nine (53) to twelve (51) per cent cane sugar, and 
reported no raffinose, no dextrose, dextrin or dextran would tend to lead 
us to the conclusion that these experimenters estimated the bodies of this 
class with the cane sugar, and perhaps with their extracting agents these 
bodies behaved in the same manner as cane sugar. As far as digestibility 
and food value is concerned they appear to be just as good as cane sugar. 
The amount of these carbohydrates found by these determinations, — (6.65) 
added to the sucrose, raffinose and invert sugar, — (3.56) amounts to 10.2], 
about the same as the earlier investigators found and estimated as cane 
sugar. 

The high digestibility factor of the hemicelluloses of the soy bean as 
extracted with dilute hydrochloric acid, compared to the low digestibility 
factor for some hemicelluloses (25) (55), would lead to the suggestion that 
hemicelluloses in general are variable in complexity of structure somewhat 
like the protein materials, and that some hemicelluloses are "near sugars," 
and that others are almost true celluloses. And, we might reasonably con- 
clude that the hemicelluloses of the soy bean are very much nearer to the 
sugars in composition and structure than they are to the true celluloses. 
As far as digestibility and nutritive value are concerned they appear to be 
almost as valuable as sugars. 

When we consider the proportion of the milled products of the soy 
bean, (8% bran and 92% meal) as we found them in an accurate separation, 
(p. 301), or allowing in the cruder miring operations for 10% waste in the 
elimination of all that might be termed bran, we would have to find either 
a very low digestibility factor for the bran, or find in it some harmful 
element not found in the meal, if we could consider ourselves justified in 
going to the expense of operating the milling processes. We have found 
only about 20% of the bran as a whole indigestible. Since 20% of 10 is 
2% of 100, we see that as far as digestible matter is concerned we would 
gain only 2% by operating the milling processes. 

As far as physical appearance is concerned, we found the bran to possess 
a rather objectionable feature. It has what might be termed a dirty opal- 
escence, while the meal has what would be called a rich golden color. The 
removal of the bran probably increases the golden richness in color of the 
meal about 10 per cent. 

The difference made in the proportions of the mineral contents of the 
soy meal by the removal of the bran (lowering the CaO from 0.31% in the 
whole meal to 0.27% in the pure meal, or 0.04% (p. 304), and increasing the 
P 2 5 — from 1.42% in the whole meal to 1.52% in the pure meal, or 0.1% 
(p. 305), would not be of material consideration in estimating the expenses 
and profits of the milling process. 

The traces of alkaloids were found in both the bran and the meal. No 
other poisons were found in either product, with the exception of a trace of 



321 

tannin in the meal. Xo notable physiological effects were experienced by 
the subject, making a day's ration solely on the bran. So the 29c increase 
in food value and the 109c gain in physical appearance of the meal is all 
that would be gained by the milling process applied to the soy bean. 

In Experiment I with the rats, we notice that all of the rats consumed 
on an average of .063 grams of food per gram rat per day. By the second 
and third experiments, we see that of the different samples of soy meal they 
ate only 0.035 and 0.033 grams of food per gram rat per day, just a little 
more than half of what they did of the balanced ration. The presence in 
the first diet of the non-nutritious agar, and the presence in the second and 
third diet of more butter, might have accounted for some of the difference, 
but not very much. So we must conclude that the soy bean has in it some- 
thing that is distasteful. 

In the second experiment we note that the rats, fed on the soy cake 
meal which had three per cent of oil left in it, ate 0.03S while those on that 
which had six per cent of oil ate 0.035, hardly enough difference to justify 
us in drawing the conclusion that the oil had anything to do with the flavor. 
But, when we note in experiment three that the rats on the diet of whole 
Boy meal ate only 0.033, we suspicion that the oil may have something to do 
with the disagreeable flavor. Again, in Experiment IV, the rats were fed 
on a diet of pure soy meal, from which nothing was separated except the 
bran. This has a very small proportion of oil and leaves the meal with 
more oil in proportion. Of this, they ate only 0.030, and we get more evi- 
dence in support of the idea. In Experiment YT, in which we fed three of 
the rats on soy meal with practically all of the fat extracted with benzine, 
they ate on an average of 0.031, but in a later experiment XVI, in which 
we merely dampened the balanced ration with benzine, same as we did in 
Experiment VI, they ate only 0.016, whereas they ate 0.058 of the same 
balanced ration when it was not so treated. This makes it appear as tho the 
benzine, which had not been completely driven from the meal, was largely 
responsible for the disagreeable taste in this diet. 

In Experiment YTII, we found that the rats consumed on an average of 
0.058 grams of a balanced ration, a ration which was agreeable to their 
taste: while when fed on the same ration with sixteen per cent of soy oil 
mixed with it. as seen in Experiment IX. they ate only 0.010. — only a little 
over two-thirds as much. And, in Experiment X, in which they had the 
same balanced ration with only four per cent of soy oil, they consumed 0.050, 
a little over five-sixths as much as with no oil at all. These two latter ex- 
periments reinforce the idea that there is a disagreeable flavor in the soy 
bean oil, and that as far as the oil is concerned we have a better flavored 
food in the commercial soy cake meal than in the whole bean meal. 

Following up the same experiments with regard to the navy bean oil, we 
find in Experiment EEI that the rats, fed on the whole navy meal, ate 0.021. 
This for the navy meal is only one-third of what they ate of the balanced 
ration and about two-thirds of what they ate of the soy meal under the same 
conditions. We see in Experiment VI that they increased this a little, (to 
0.026) when the oil was extracted. But, we see by comparing Experiment 
VTTT with Experiment IX that the restoration of the navy bean oil made 



322 

no difference in the amount which they ate before the oil was put back and 
afterward. Then, when we put into the balanced ration four per cent of 
navy oil, we found as in Experiment X that it did make some difference, 
bringing their average down from 0.058 to 0.049. This indicates that in the 
raw navy bean there is something distasteful. It shows, too, that the flavor 
might be due in part to the oil, if there was sufficient of the oil in the navy 
bean. It appears then, so far as the oils of the two beans are concerned, 
that one is as distasteful as the other. 

Experiment VII shows that the rats will eat the soy meal with a little 
more relish when it is extracted with hot 95 per cent alcohol. The amount 
eaten in this experiment compared to what they ate in Experiment VI, 
which is 0.035 as against 0.031, and indicates that the alcohol also has re- 
moved something distasteful or that the alcohol, itself, which was not dried 
off from the material, is not so distasteful as is the benzine. Experiment 
XVII, in which the rats were found to eat 0.051 compared to the 0.058 of 
Experiment VIII, the only difference being that the balanced ration of Ex- 
periment XVII was barely moistened with alcohol and then allowed to dry 
for twenty-four hours, shows that the alcohol does interfere with the taste 
to some extent, but not so much as does the benzine. This fact would add 
a little to the indications that the alcohol takes away something that is dis- 
tasteful. In Experiments XII and XIII, in which the organic acids and waxes 
respectively were added to the balanced ration in the same proportions in 
which they were extracted from the meal, the rats ate 0.044 for the acids 
and 0.045 for the waxes as against 0.058 for the food without them. This 
confirms the opinion that the alcohol takes away some of the disagreeable 
flavor. Experiment XI, the alcohol extracted sugars were added to the 
balanced ralion in the same percentage as extracted. Of this, the rats con- 
sumed 0.055 grams, showing that the disagreeable taste is not in the sugar 
fraction of the alcohol extract, but in the organic ncids and wax, and is 
about equally divided between the two. 

Following thru the same experiments with the nnvy bean meal, we find 
that the alcohol extraction raises the navy meal in the rats' estimation from 
the amount of 0.026, benzine extracted to the amount of 0.040 alcohol ex- 
tracted; while for the soy bean the increase was merely from 0.031 to 0.035. 
Adding the alcoholic extract of the navy bean to the balanced ration re- 
duced the average consumption from 0.058 to 0.046, 0.045, 0.048 for the 
carbohydrates, acids and waxes respectively; as can be seen in experiments 
XI, XII and XIII, respectively. These experiments show that by far the 
greater portion of the disagreeable flavors of the navy bean exist in the 
alcohol extracted materials, about equally distributed among the carbo- 
hydrates, acid and wax mixtures. 

Experiment V, in which the bran was discarded in ca^e of both the 
soy and the navy bean meal, we find an average consumption of 0.022 for 
the navy and 0.030 for the soy, showing that as far as flavor is concerned 
there is no point in removing the bran from either bean. 

Experiment V, in which the bran alone was fed, shows an average 
consumption of 0.036 for the navy and 0.043 for the soy, a considerable 
increase over that of the whole meal or pure meal in each case. This is 



323 

what we would expect as far as the flavor of the soy bean oil is concerned, 
ror in our analysis we found less than two per cent of oil in the soy bran. 
As far as the taste of the acids and waxes is concerned, it is a little differ- 
ent than might be expected, for we found that the bran contained twice 
the percentage of acids and about three times the percentage of waxes 
found in the meal. But, on the other hand there is more tasteless material 
and more material that has an agreeable flavor in the bran than in the 
meal because it contains a larger amount of fiber and carbohydrates. Then, 
if the whole meal is used, since only eight per cent of the whole meal is 
bran, the bran could not be depended on to influence the taste one way or 
another. 

By Experiments XIV, XV. XIX and XX we find that neither water nor 
soda extractions make appreciable difference in the flavor of the products. 

From the above considerations, it would seem quite evident that the 
soy cake meal furnishes a little better food than does the whole soy bean, 
and that it comes much nearer furnishing a substitute for meat than does 
the navy bean. 

SUMMARY 

Porridge made of soy cake meal well cooked, which was considered 
rather distasteful at first, was not considered so distasteful after eating 
three or four meals. It becomes very palatable after a three or four days ' 
diet on it. 

There are no apparent discomforts in man from a diet consisting of 
soy cake meal, milk, butter and sugar, the soy bean meal furnishing 25 
per cent of the calories. 

The protein of the meal when thoroly cooked is about 91 per cent 
digestible by man (making metabolic corrections.) This compares favorably 
to the proteins of patent wheat flour. 

The carbohydrates as a whole, altho consisting largely of dextrin, 
pentosan and galactan, are about 94 per cent digestible. 

A more extended study of the digestibility of the different carbohydrates 
taken separately proves that the sucrose, which amounts to about 3 per 
cent, is practically 100 per cent digestible: that the rafnnose, which amounts 
to about 1 per cent, is thoroly digestible; that the dextrans or dextrins are 
essentially 100 per cent digestible; that the little bit of starch, amounting 
to less than one per cent, is thoroly digestible; that the hemicelluloses. 
amounting to about six per cent, are about 93 per cent digestible, and that 
the cellulose is about 77 per cent digestible. 

The bran can be separated easily from the soy bean by milling. It can be 
more easily and more completely separated than can the bran of wheat. The 
bran makes up about eight per cent of the soy bean and is composed mainly of 
crude fiber and nitrogen free extract. The crude fiber amounted to about 37% 
and the nitrogen free extract amounted to about 43%. 

Digestibility experiments on the bran showed that the nitrogen free ex- 
tract, including the hemicelluloses and the waxes, is about 84% digestible, 
which is much less than that of the whole bean. This we judge is on ac- 
count of the large amount of waxes in the nitrogen free extract of the bran. 



324 

A diet consisting of well cooked soy bean bran appeared to have no ill 
effects physically or physiologically. No noticeable amount of gas indicating 
fermentation, as is the case with the navy bean bran, was noticed with the 
soy bean bran. One day's diet exclusively of the bran produced small 
amounts of gas, but nothing especially distressing. However, the bran diet 
was unpalatable. 

The calcium oxide content of the bran was found to be 0.8% and that 
of the meal 0.27%. The removal of the bran from the bean lowers the 
calcium oxide content from 0.31% to 0.27%, or a lowering of 0.04%. 

The phosphorus pentoxide content of the bran was found to be 0.27%, 
and that of the meal to be 1.52%. The removal of the bran from the bean 
raises the phosphorus pentoxide content from 1.42% to 1.52%, an increase 
of 0.1%. 

No salicylic acid was found in either the bran or the meal. No hydro- 
gen cyanide or cyanates were found in either the bran or the meal of the 
samples tested. 

A very slight trace of tannin was found in the meal, but no trace of 
tannin could be found in the bran. A slight trace of alkaloids was found 
in both the meal and the bran. 

The raw soy bean meal seems almost as distasteful as is the navy bean 
meal, judging from our experience with white rats. 

Soy bean oil contains some of the unpleasant flavor found in the bean. 
Cooking does not improve the flavor of the oil very much. 

A little of an unpleasant flavor was found to be present in the navy 
bean oil. Cooking made very little improvement in this ease. 

A disagreeable flavor was found in the organic acids of the soy bean. 
This was practically all removed by cooking. The same sort of flavor of 
the navy bean exists in the carbohydrates, acids and waxes about equally 
distributed. Cooking makes great improvement in this case. 

As far as flavor is concerned there is no point gained in removing the 
bran from either the soy bean or the navy bean. 

The beany flavor and some of the disagreeable taste can be easily 
removed from the soy bean by steam distillation, but the disagreeable 
flavor in the oil cannot be removed in this way. 



The greater part of the laboratory work for the above article was 
done in the laboratory of the Department of Agriculture and Soils, in the 
Ohio State University, under the leadership of Dr. J. F. Lyman. The article 
was submitted and approved as partial fulfillment of the requirements for 
the degree of Doctor of Philosophy granted by the Ohio State University 
in 1919. 

The author wishes also to thank Dr. Park of the Farm Crops Department 
of the same university for his suggestions concerning the milling of the 
soy bean and for the use of his mills in the process. 



325 

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328 



CONTENTS 

I. INTEODUCTION Page 

Extent of Production 278 

Human Food Preparation by Different Nations 250 

Varieties and Chemical Composition 281 

Character of Carbohydrates, its Bearing on Nutrition 282 

Character of Fats, its Bearing on Nutrition 283 

Character of Proteins, its Bearing on Nutrition 283 

Vitamines of the Soy Bean 284 

Mineral Constituents of the Soy Bean 285 

Comparison to Other Legumes Used as Food 286 

Digestibility of Soy Products 286 

II. EXPEELMENTAL PAET. 

Character of Materials Used 287 

Determination of Digestibility of Soy Bean Products 288 

Nutritive Value of the Nitrogen Free Contents of the Soy Bean.. 291 

The Determination of the Parts 292 

Alcohol Extract 

Not Precipitated by Lead 292 

Precipitated by Lead 293 

Water Extract of Alcohol Insolubles 294 

Malt Digestion of Water Insoluble residue 294 

One per cent HC1 Extract of residues 295 

Sodium hydroxide (1.25 per cent) extract of residues 296 

Clorination of residues, true cellulose 296 

Waxes, Eesins, Tannins and Color substances 296 

Digestibility of the Materials in the Nitrogen Free Content.. 298 

The Milling of the Soy Bean 301 

Proportions of bran, germ and cotyledon 301 

Composition of various parts 301 

Digestibility of Soy Bean Bran and effect of milling 

on nutritive value of the soy bean products 302 

Mineral constituents of bran and meal from soy beans 304 

Toxic and Disagreeable or Unpalatable Substances found 

in Soy Beans 305 

III. DISCUSSION OF EESULTS 319 

IV. SUMMAEY 323 

V. BIBLIOGEAPHY 323 



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